Chapter 22. Troubleshooting Desktop and Mobile Operating Systems

This chapter covers the following subjects:

Troubleshooting Common Symptoms—Learn the symptoms of problems with Windows, Linux, and OS and discover their solutions in this section.

Tools for Troubleshooting Software—Discover additional Windows tools and OS X and Linux repair techniques.

Troubleshoot Mobile OS and Application Issues—Find out how to deal with system lockout, issues, when and how to perform soft and hard resets, and uninstall/reinstall apps to solve problems.

Troubleshooting PC Security Issues—Learn the symptoms of malware infection, tools you can use to fight back, and a systematic approach to removing infections.

With the widespread use of mobile devices, troubleshooting is now more than just solving problems with computers. However, many of the same principles apply whether solving problems with computers, peripherals, or mobile devices: knowledge of products and operating system functions, understanding of the tools needed to diagnose and repair problems, and a determination to avoid data loss except when unavoidable. This chapter helps you apply these principles.

220-902: Objective 4.1 Given a scenario, troubleshoot PC operating system problems with appropriate tools.

220-902: Objective 4.2 Given a scenario, troubleshoot common PC security issues with appropriate tools and best practices.

220-902: Objective 4.3 Given a scenario, troubleshoot common mobile OS and application issues with appropriate tools.

220-902: Objective 4.4 Given a scenario, troubleshoot common mobile OS and application security issues with appropriate tools.

In Windows 8/8.1/10, STOP errors now look like the example shown in Figure 22-2. In these versions of Windows, the STOP error is listed by name.

Incompatible or defective hardware or software—Start the system in Safe Mode and uninstall the last hardware or software installed. Acquire updates before you reinstall the hardware or software. Exchange or test memory. Run SFC/scannow to check for problems with system files.

Registry problems—Select Last Known Good Configuration (Windows Vista/7) as described later in this chapter and see whether the system will start. Using System Restore can also be used to revert the system and Registry to an earlier state; see the “System Recovery Options (Windows)” section later in this chapter for details.

Viruses—Scan for viruses and remove them if discovered.

Miscellaneous causes—Check the Windows Event Viewer and check the System log. Research the BSOD with the Microsoft Support website.

To learn how to start Windows in Safe Mode, see “Safe Mode (Windows),” p.1111, this chapter.

The solution might involve one or more of the following changes to your system:

Changing the system registry. Sometimes, an automated registry repair tool can be downloaded to perform these changes for you. Whether you make the changes manually or automatically, back up the registry first!

Removing a newly added component. For example, to solve the error shown in Figure 22-1, I removed a memory module I had just added to my computer.

Replacing components such as memory.

Upgrading an application.

Downloading and installing a hotfix for your operating system.

On some systems, auto restart is enabled for STOP/BSOD errors, so the error message shown in the previous figures appear for only a moment before the computer restarts. For solutions, see the “Spontaneous Shutdown/Restart” section later in this chapter.

It appears most often when an application or OS X itself has become unresponsive. For this reason, it is sometimes referred to as the “pin wheel of death.”

Some causes of OS X unresponsiveness include:

Lack of system RAM—If your OS X device frequently displays the pin wheel and the device’s RAM can be upgraded, do so.

Less than 10 percent free space on the OS X system drive—Free space is used as a swapfile to substitute for RAM. Remove unwanted apps and save data to external or cloud storage to free up space. Some experts suggest keeping at least 20 percent of the OS X system drive free.

Damaged application—Run Disk Utility using the Verify Disk Permissions option (in OS X versions prior to El Capitan).

Some solutions include:

If a particular application causes unresponsiveness, open the ~Library/Preferences folder, find the .plist file for the app, and drag it to the trash. The .plist file will be rebuilt.

Use Activity Monitor to view CPU, memory, energy, disk, and networking performance stats. For OS X 10.9 and later, see https://support.apple.com/en-us/HT201464. For OS X 10.8 and earlier, see https://support.apple.com/en-us/HT201538.

Upgrade to the latest OS X version and keep it updated.

Use the Force Quit command to terminate an application that won’t respond. It’s available from the Apple menu or by pressing Command-Option-Esc. Select the app and click Force Quit.

BOOTMGR is missing—This message displays if the bootmgr file is missing or corrupt. This black screen will probably also say Press Ctrl+Alt+Del to Restart; however, doing so will probably have the same results.

The Windows Boot Configuration Data file is missing required information—This message means that either the Windows Boot Manager (Bootmgr) entry is not present in the Boot Configuration Data (BCD) store or that the BootBCD file on the active partition is damaged or missing. Additional information you might see on the screen includes File: BootBCD, and Status: 0xc0000034.

There are two ways to repair a missing BOOTMGR file:

Boot to the System Recovery Options and select the Startup Repair option. This should automatically repair the system and require you to reboot.

Boot to the System Recovery Options and select the Command Prompt option. Type the bootrec /fixboot command, as shown in Figure 22-4.

For more about these steps, see https://support.microsoft.com/en-us/kb/2622803.

To repair the BCD store, use this 3-step process:

Step 1. Boot to the System Recovery Options and select the Startup Repair option. This should automatically repair the system and require you to reboot. If not, move on to the second method.

Step 2. Boot to the System Recovery Options and select the Command Prompt option. Type bootrec /rebuildbcd. If the Bootrec.exe tool runs successfully, it presents you with an installation path of a Windows directory. To add the entry to the BCD store, type Yes. A confirmation message appears that indicates the entry was added successfully. Restart the system.

Step 2b. If the Bootrec.exe tool can’t locate any missing Windows installations, you must remove the BCD store and then re-create it. To do this, type the following commands in the order in which they are presented. Press Enter after each command.

Bcdedit /export C:BCD_Backup
ren c:ootcd bcd.old
Bootrec /rebuildbcd

You can find more information on this process at the following link:

Windows Vista, 7—http://support.microsoft.com/kb/927391 (also works with Windows 8/8.1/10)

Windows 7—http://support.microsoft.com/kb/2004518

If Windows boots to Safe Mode or displays an Advanced Boot Options menu, see the “Safe Mode (Windows)” section later in this chapter for more information.

When Linux is run in Recovery mode, the screen is full of commands (most distros hide startup commands by default). From the Recovery menu (see Figure 22-7), you might be offered a variety of options to fix your system (varies by distribution). If a Linux distribution doesn’t have a menu offering these options, most can be run from the command prompt (might require su or sudo to run).

Here is more information about the Recovery Menu options in Figure 22-7.

resume—Continues normal boot process

clean—Frees up space on your file system (use if disk is about full)

dpkg—Repairs broken software (use if software installation failed); be sure to enable networking first with network

failsafex—Enables system to boot to GUI

fsck—Repairs file system errors

grub—Updates grub boot loader

network—Enables networking, which is turned off in recovery mode

root—Opens system in read/write root shell mode (for experts only)

system-summary—Displays information about the system

Other startup problems:

Some BIOS will not boot to Linux because Linux partitions don’t use the MS-DOS boot flag. To fix the problem, start the system from a Live CD or Live USB drive and open a terminal session. Use the command sudo fdisk /dev/sda and view partition table settings by giving the p (print) command. A bootable partition is marked as a (active). If no partition is marked as active, use the a command to mark this partition as active, save changes with w (write), and restart the system after removing the live CD.

If Linux is being installed in a separate disk partition on a system running Windows 8/8.1/10, it is usually necessary to disable the BIOS setting for Secure Boot (also known as Windows 8/10 mode) to enable booting from a Linux USB drive or optical disc. After installation, to boot either Windows 8/8.1/10 or Linux, a new version of the grub bootloader must be installed that adds support for EFI/UEFI with the command sudo apt-get install grub-efi. For more details, see http://askubuntu.com/questions/459979/operating-system-not-found-error-when-booting-from-usb-in-windows-8.

Restore from Time Machine Backup—Restores the system from a Time Machine backup

Reinstall OS X—Reinstalls OS X

Get Help Online—Opens online help and remote diagnostics options

Disk Utility—Repairs problems with hard drives

To boot from a different partition than usual, such as a Boot Camp partition, start up your OS X system and hold down the Alt/Option key until a list of bootable drives appears. Select the drive to use.

For details, see http://support.microsoft.com/kb/929135. See “MSCONFIG (Windows)” later in this chapter for more.

If a system needs to be available at all times and STOP/BSOD errors are rare, it might be preferable to configure the system to restart automatically. (Different versions of Windows enable or disable this option by default.) To change this option, follow these steps:

Step 1. Open the System Properties window. Click or tap Advanced System Settings.

Step 2. Click the Advanced tab.

Step 3. Click Settings under the Startup and Recovery section.

Step 4. To enable auto restart, select the checkbox for Automatically Restart under the System Failure section (see Figure 22-9). To disable auto restart if it is already enabled, clear this checkbox.

Press a key to restart. To learn more about reporting a kernel panic, see the “Kernel Panic (OS X/Linux)” section later in this chapter.

To test your system after a kernel panic or any other issue, restart your system and run Apple Diagnostics (systems built in 2013 or later), or Apple Hardware Test (older systems).

On systems with Apple Diagnostics or Apple Hardware Test built in, disconnect external drives, docking stations, and network adapters, open the Apple menu and select Restart. To launch the diagnostics test, hold down the D key while the system restarts. Follow the onscreen prompts to test your system. For more information, see https://support.apple.com/kb/PH21879. For more about kernel panics, see https://support.apple.com/en-us/HT200553.

In most cases, updating the drivers with the Drivers tab solves the problem. If this does not resolve the problem, see http://support.microsoft.com/kb/943104 or search for information about the specific device with an error to learn what to do next.

A device that is detected as an Unknown device has no driver installed. Install the driver, then open Device Manager to see if the device is now working. In some cases, it might be necessary to remove the device before installing the driver, then reconnecting/reinstalling the device after the driver is present.

File deletion or renaming

Damage from virus or malware

Before attempting to fix the problem, check your system for viruses and malware and resolve any detected infections.

If the file is a Windows system DLL, use SFC (System File Checker) to check your Windows files and reinstall a replacement.

If the file appears to be part of an application, use Uninstall a Program in Control Panel to see if there’s a repair option for the program. If this option doesn’t work or is not available, uninstall and reinstall the program.

A service might not start for the following reasons:

Hardware used for the service is not present. For example, wireless network configuration will not run automatically if a wireless adapter is not installed.

Other services that are used by the service are not running. In this case, an error such as “The Dependency Service or Group Failed to Start” appears.

The service requires login information that has not been provided.

The service has stopped due to previous errors and is not configured to restart automatically.

To learn how to manage services, see “Services (Services.msc),” p.764, Chapter 15.

To troubleshoot a service that didn’t start, open a Terminal session as root and run the service’s command to see if there’s an error message.

To disable loading all of these items for troubleshooting, start OS X in Safe Mode (press the power button while holding down Shift). For more troubleshooting in Safe Mode, see https://support.apple.com/en-us/HT201262.

Check for Solutions Online—Choose this option to see whether an updated program or a patch is available.

Run Program—Windows will run the program, but it is not likely to work.

Cancel—Windows will not run the program.

Get an updated version of the program, either by selecting the Check for solutions... option or by manually searching for and downloading an update.

For more solutions, see “Compatibility Mode,” p.681, Chapter 14.

System not configured for maximum performance—To solve this problem, set the Power setting to High Performance using the Power options icon in the notification area or the Power options in Control Panel. This option is not available on tablets.

Drive containing paging file and temporary files is nearly full or badly fragmented—The paging file and temporary files are normally stored on C: (system) drive. If this drive has less than 15 percent free space, performance can suffer. Use Disk Cleanup in drive properties to remove unwanted files, check the drive for errors, and defragment it. If you have more available space on a different drive, use the Advanced tab in System properties to change the location of the paging file and temp files.

System is overheating and CPU is running at reduced speed—Remove dust and dirt on the CPU and system fans. Check for adequate airflow through the system. Change back to Balanced power setting.

Add RAM—Exceed the minimums recommended for the version of Windows in use for better performance.

Check for viruses and malware—Especially important if performance has suddenly plunged.

Check for Registry errors—The Piriform CCleaner is widely used for this task.

Use the performance troubleshooters in your version of Windows—Search for “performance troubleshooter.”

Remove unneeded startup programs—With recent versions of Ubuntu, use the Startup Application manager. With Fedora or other distributions, install GNOME-TWEAK and use its startup application manager.

Install more RAM—Exceed the minimums recommended for the version of Linux in use for better performance.

Disable unneeded system services—System services are typically located in the /etc/init.d directory (folder). Depending on your distribution, you might have a control center that can be used to disable system services, or you might need to use the Nautilus file manager, right-click a service, go to Properties > Permissions, and unclick the Execute: Allow Executing File as Program. To determine what a particular service does, look it up in the manpages for your distribution.

If your MacBook Pro was built in 2012 or earlier and uses a hard disk, replace it with an SSD. Step-by-step instructions are available at www.cnet.com/how-to/upgrade-your-macbook-install-ssd-hard-drive/.

Add more RAM.

Use Disk Utility to remove apps you no longer need.

Use System Preferences to disable unneeded startup apps.

Be sure to install OS X updates as they become available.

Remove unwanted Dashboard programs (widgets).

Even if you don’t believe there are serious problems with the system, it is usually best to start the system in Safe Mode and then perform the shutdown/restart procedure from the Windows desktop. If there are no serious problems with the system, it usually restarts correctly.

Windows 8/8.1/10 recover from an improper shutdown without user intervention.

This File Does Not Have a Program Associated with It for Performing This Action. Please Install a Program, or if One Is Already Installed, Create an Association in the Default Programs Control Panel.

In Windows Vista/7, open Default Programs in Control Panel and select Associate a file type or protocol with a program.

In Windows 8/8.1/10, open the Charms menu, and select PC Settings > Search and apps > Defaults > Choose default apps by file type.

Although missing bootloaders can be restored with manual processes, bootable repair programs are recommended. Some of these include:

Boot-repair (https://sourceforge.net/p/boot-repair/home/Home/)

Rescatux (www.supergrubdisk.org/rescatux/)

SystemRescueCd (www.system-rescue-cd.org/SystemRescueCd_Homepage)

These programs can be installed to a bootable CD or USB flash drive. They work by scanning the drive for operating systems and use that information to recreate GRUB or LILO and its entries, including Windows.

With Linux, depending on the distribution and the cause of the kernel panic, you might see a Kernel Panic error message on-screen, or the clues might simply be the Num Lock and Caps Lock indicator lights flashing on the keyboard and a completely unresponsive Linux installation.

Unlike normal shutdowns, which are logged by Linux, a kernel panic itself isn’t logged. By examining Linux log files and viewing the times, you might be able to get some clues about what happened, but this can be frustrating and time-consuming.

Check the following:

Was new hardware installed shortly before the kernel panic?—Remove the hardware or update its drivers. Some hardware vendors now provide Linux drivers, so try them instead of open-source versions.

Was the system overheating?—Install Psensor (http://www.tecmint.com/psensor-monitors-hardware-temperature-in-linux/) to provide real-time monitoring of system temperature. If a kernel panic occurs again, you will have information about overheating.

Was new software installed?—Uninstall it and check for updated versions.

Is a stable update to the Linux distribution available?—Install it.

Is system memory working properly?—Run a memory test. Some distributions, such as Ubuntu, include Memtest86+ as an advanced boot option. Otherwise, it can be downloaded from www.memtest.org.

Before an additional display can be used by an OS, make sure it is plugged into AC power and a video port and turned on.

To use an additional display with Windows Vista:

Step 1. Right-click an empty area of the desktop and select Personalize.

Step 1a. From the Vista Personalize menu, click Display Settings.

Step 2. If the additional display is not visible, click Detect.

Step 3. To enable the additional display, click it.

Step 4. Click Apply and then click OK ; it mirrors the contents of the primary display. One or both displays might change resolution.

Step 5. To use it as a mirror, click the Extend My Windows Desktop onto This Monitor.

Step 6. Adjust the screen resolution as needed for the second display. To determine usable resolutions, check the documentation for the display.

Step 7. Click Apply and then click OK to use the settings.

To use an additional display on Windows 7/8/8.1/10 using the Display properties sheet:

Step 1. Before turning on the computer, plug in the appropriate video cable to the video port.

Step 2. Turn on the external monitor, TV, or projector.

Step 3. Turn on the computer.

Step 4. Right-click an empty area on the desktop and select Screen Resolution.

Step 5. If the secondary screen is not detected, click Detect.

Step 6. Multiple displays are initially configured as mirrored, and resolutions might be adjusted automatically to enable both displays to run at the same resolution (see Figure 22-13).

Step 7. To use extended desktop, open the Multiple Displays menu and select Extend These Displays.

Step 8. Click Apply.

Step 9. Select the second display and adjust the screen resolution as needed. To determine usable resolutions, check the documentation for the display.

Step 10. Drag the display to match its location relative to the original display (see Figure 22-14).

Step 11. Click Apply and then click OK to use the settings.

Step 1. Connect the additional display and turn it on.

Step 2. Open System Preferences > Displays.

Step 3. A window opens for each display. In the Optimize window, you can optimize for the new display, or choose a scaled display from a choice of resolutions (see Figure 22-15).

Step 4. Click the Arrangement tab.

Step 5. By default, the displays are mirrored.

Step 6. Drag the new display to the correct position relative to the original display (which is marked with a menu bar across the top of the icon (see Figure 22-16). The menu bar can be dragged to the additional display if desired.

Step 7. To use the additional display as an extended desktop, clear the Mirror Displays checkbox.

For more information, see https://support.apple.com/en-us/HT202351 and https://support.apple.com/en-us/HT202780.

Step 1. Open the Settings app and click Display.

Step 2. If only one display is visible, and other displays are plugged in and turned on, click Detect Displays.

Step 3. If a mirrored display is desired, make sure the Mirror box is checked. For an extended desktop, make sure it is not checked.

Step 4. Select each display and adjust its resolution. When running Linux in a VM (as shown in Figure 22-17), displays are listed as “Unknown display.” When running Linux on physical hardware, displays are listed by brand and size.

Step 5. Drag displays into position and click Apply.

Some Linux distributions will not retain multiple monitor alignment positions after restarting. To solve this problem, a startup script that will provide the monitor alignments needs to be created.

A good example for Ubuntu is available from: http://bernaerts.dyndns.org/linux/74-ubuntu/309-ubuntu-dual-display-monitor-position-lost.

For Fedora (and other distributions using KDE or GNOME GUIs), see http://tech.isatya.in/post/9090316930/setting-forcing-changing-fedora-15-screen.

Before attempting to repair the MBR or GPT, restart the computer, enter the BIOS setup program, and check the following:

Make sure the system drive is correctly identified in the system BIOS.

Make sure the system drive is listed before other bootable drives in the boot sequence or boot order menu.

Save any changes needed, and restart the computer. If the same error is displayed, restart the computer with the Windows installation media.

With Windows, start the Windows Recovery Environment and use Startup Repair.

To learn more, see “Safe Mode (Windows)” and “To learn more, see the “Safe Mode (Windows)” section later in this chapter.

If Linux is normally started with a GUI, but fails to launch the GUI, hold down the Shift key when starting Linux. From the GRUB2 menu, boot into Recovery mode. Use a startup option that loads failsafeX, or run it after the startup process is complete from the terminal command prompt.

To solve this problem, restart Windows in limited resolution (VGA) mode, open the Advanced Display properties sheet, and select the correct refresh rate (typically 60Hz for LCD or LED panels or integrated LCD or LED displays).

RAID array (if used for boot) is properly configured

Drives are properly identified and configured (AHCI, SATA 6Gbps, and so on)

Secure Boot on for running Windows 8/8.1/10 only, or disabled if dual-booting with Linux or older Windows versions

Memory recognized correctly

Boot sequence

Use the Overview and Summary window or the branches of the Event Viewer or Computer Management Console to locate the log message you need to read. Look for Critical errors (marked with a white X on a red circle) first and then Warnings (yellow triangle). Frequent errors or warnings that point to the same program or device can indicate a serious problem (see Figure 22-18 and Figure 22-19). You might need to update drivers for a problem device, obtain a software update for a problem program, or remove the device or program and replace it with a different one to resolve the problems.

To start System Recovery Options manually with Windows Vista/7, see “Repair Discs,” this chapter, p. 1108.

To restart the system and use System Recovery Options in Windows 8/8.1/10:

Step 1. Hold down the Shift key and click the onscreen power button at the Windows login screen.

Step 2. Select Restart.

Step 3. Select Troubleshoot.

Troubleshooting options:

Refresh your PC to remove apps not from the Windows Store, reinstall apps from the Windows store, and keep the user’s files and settings.

Reset your PC to return it to its factory condition. All users’ files, settings, and programs will be lost.

Select Advanced options for other repair choices:

System Restore to return the system to its condition as of a restore point (System Restore must be enabled for this to be possible)

System Image Recovery to restore a system image (create the image with the System Image Backup link in File History)

Startup Repair to repair a system that won’t start

Command prompt to run a command-line program such as bootrec

UEFI firmware settings to enter the UEFI firmware (BIOS)

Startup settings to get access to the special startup options (also known as the F8 menu startup options).

Figure 22-20 illustrates these three dialogs.

Windows Repair Disc enables the user to run WinRE from a bootable CD or DVD. Repair discs (also known as repair disks) can be created with Windows Vista SP1 or higher and with any release of Windows 7. Windows Repair Disc can be used to restart the system to run the Windows Recovery Environment (see Figure 22-21).

To restart the computer with a repair disc, insert it, turn on or restart the system and, if prompted, press a key to boot from the disc.

Windows PE for Windows 10 is described at https://msdn.microsoft.com/en-us/library/windows/hardware/dn938389(v=vs.85).aspx. It can be downloaded as part of the Windows Assessment and Deployment Kit for Windows 10.

To use Regsvr32.exe, open a command prompt as administrator. Go to the folder containing the file(s) you need to reregister.

The basic syntax to register a program file with Regsvr32 is:

Regsvr32 filename.ext

For example, to reregister a file called jscript.dll in the current folder, use the following:

Regsvr32 jscript.d11

With Windows 8/8.1/10, getting to the Advanced Boot Options menu takes more steps. Press the Power button on the login screen, hold down the Shift key, and click/tap Restart. Select Troubleshoot > Advanced Options > Startup Settings > Restart. The Windows 8/8.1 startup settings menu (see Figure 22-23) adds a couple of new features but looks similar to that of Windows 7.

The Windows 10 Startup Settings menu has similar options to the Windows 8.1 version, but is more graphical (see Figure 22-24).

Here’s what the options do:

Safe Mode—Starts the system with a minimal set of drivers; can be used to start System Restore or to load Windows GUI for diagnostics.

Safe Mode with Networking—Starts the system with a minimal set of drivers and enables network support.

Safe Mode with Command Prompt—Starts the system with a minimal set of drivers but loads command prompt instead of Windows GUI.

Enable Boot Logging—Creates an ntbtlog.txt file.

Enable low-resolution video—Uses a standard VGA driver in place of a GPU-specific display driver, but uses all other drivers as normal.

Last Known Good Configuration—Starts the system with the last configuration known to work; useful for solving problems caused by newly installed hardware or software.

Debugging Mode—An advanced diagnostics tool that enables the use of a debug program to examine the system kernel for troubleshooting.

Disable automatic restart on system failure—Prevents Windows from automatically restarting if a STOP (BSOD) error causes Windows to fail. Choose this option only if Windows is stuck in a loop where Windows fails, attempts to restart, and fails again.

Disable driver signature enforcement—Allows drivers containing improper signatures to be installed.

Disable early launch anti-malware protection—Use this when a legitimate driver is mistaken for malware by Windows 8/8.1/10’s Early Launch Anti-Malware Protection feature.

Start Windows Normally—Can be used to boot to regular Windows. This option is listed in case a user inadvertently presses F8 but does not want to use any of the Advanced Boot Options.

If Windows 7 or Vista fails to start properly and then restarts automatically, they normally display the Windows Error Recovery screen and give you the following options: Safe Mode, Safe Mode with Networking, Safe Mode with Command Prompt, Last Known Good Configuration, and Start Windows Normally. This means that Windows has acknowledged some sort of error or improper shutdown and offers a truncated version of the Advanced Boot Options menu.

Table 22-1 lists typical problems and helps you select the correct startup option to use to solve the problem.

If you need to perform tasks that might change computer configuration from the normal Windows desktop, be sure to run command prompt as elevated (administrative mode):

Search for CMD, right-click it, and select Run as Administrator (Windows Vista/7).

With Windows 8/8.1/10, press Windows key+X and select Command Prompt (Administrative).

Windows 8/8.1/10 provide Refresh and Reset as additional alternatives.

For OS X Recovery (Lion release and later), see https://support.apple.com/en-us/HT201314.

Use Recovery System on your startup drive to reinstall the most recent OS X release installation on that computer; Internet Recovery installs the OS X version the computer was originally shipped with.

A Linux repair installation is destructive, so the system should be backed up first. Use a repair disc (discussed earlier in this chapter) to repair the system if possible first.

System Lockout

Hard reset

Soft reset

Adjust configurations/settings

Uninstall/reinstall apps

The following sections discuss these issues and the solutions.

If it’s an Android phone, make sure you know your Google (Android) login information. You are prompted to provide this if you are blocked. If you can provide this when prompted, you are logged back into your device. Be sure to change the password, PIN code, or pattern code. If you don’t have this information, you might need to perform a hard reset on the phone. This wipes out all apps and data.

On an iPhone, if it has locked you out, you can use iTunes to back up your device before restoring it if you have previously used iTunes for this task. See https://support.apple.com/en-us/HT204306 for more information and how to erase your device.

Press and hold the power button until you are prompted to turn off the device, then tap Power Off. To turn the device back on, press and hold the power button until the device restarts.

Remove the battery. After a minute or two, reinstall the battery and restart the device.

Press and hold the power button and volume down button until the device restarts.

On an iOS device, some people use the term “hard reset” to refer to a reset that clears the iOS firmware and can help solve problems with unresponsive hardware, botched updates, and other issues, but does not erase any data or apps. Apple prefers to use the term “restart” or “forced restart” instead. Here’s how to do a restart.

Step 1. Press and hold Sleep/Wake until the Slide to power off slider appears.

Step 2. Drag the slider to off and then wait a few seconds.

Step 3. Press and hold Sleep/Wake until the device displays the Apple logo.

If this doesn’t work, try a forced restart:

Step 1. Hold down the Sleep/Wake and Home buttons for about 10 seconds until the Apple logo is displayed.

See https://support.apple.com/en-us/HT201559 for more information.

If you decide that you need to erase your iOS device so it can be given away or sold, this can be done with Settings > General > Reset > Erase All Content and Settings. See https://support.apple.com/en-us/HT204686 for more information.

Before doing a hard reset on an Android device:

Step 1. Back up the device if possible.

Step 2. Try a soft reset.

Step 3. If you must perform a hard reset, make sure the device is charged.

Step 4. Unplug the device from power.

Step 5. Turn it off.

Step 6. Use the keystroke(s) for your smartphone or tablet and version of Android.

As an example of step 6, with recent Samsung Galaxy smartphones:

Step 1. Press and hold Volume Up, Home, and Power at the same time.

Step 2. Release the Power key only when the Galaxy logo is displayed or the phone vibrates.

Step 3. From the Android system recovery screen, select wipe data/factory reset (use the volume keys to scroll and Power to choose this option).

Step 4. After the factory reset is over, select Reboot system now to restart a phone empty of user data with factory settings only.

Table 22-3 lists typical settings for iOS and where to make them.

Windows 10 Mobile uses the Settings menu for configuration. It is similar to the Windows 10/Windows 10 Pro versions for desktop and laptop computers.

With a cellular data connection, move to a different location, preferably near a window or outside the building, or adjust how you hold the phone.

To determine the cellular signal strength in dB for a smartphone, use the Field Test Mode. For more information for iOS and Android phones, see https://www.repeaterstore.com/pages/field-test-mode. Note that a stronger signal is indicated by a lower value.

Check connection speeds with the case on and off to see if it is affecting performance. Ookla Speedtest is available from Google Play and the App Store to test performance over cellular data and Wi-Fi connections.

See the “Force Stop” section later in this chapter.

No connection to a 4G network—Check the network indicator at the top of your smartphone or cellular-equipped tablet to determine the network connection type.

A weak 4G or Wi-Fi signal—With Wi-Fi, switch to a stronger SSID signal if possible. With 4G, use a cell tower scanner to locate a stronger cell tower.

“Unlimited” Data Plan speed caps after reaching 4G speed limit per billing period—Some of the providers who offer “unlimited” data plans drastically reduce speed after a certain level of data is transferred during a billing period. Check data usage and set up a warning to be displayed before you reach this goal or consider switching users to a different plan.

To disable this feature, check the Wi-Fi settings on your smartphone. On an AT&T Android phone, for example, go to Settings > Connections > Wi-Fi > More > Advanced > Disable Auto Connect.

On an iPhone, go to Settings > Wi-Fi and then turn off Ask to Join Networks.

To prevent reconnections to a previously used network, select the network and tap Forget.

Turn off Bluetooth when you do not use Bluetooth devices.

When you use Bluetooth devices, make sure your mobile device requests a code from a device attempting to pair with it. You can do this by attempting to pair a Bluetooth-enabled device in your possession with another Bluetooth-enabled device.

Step 1. Enable encryption.

Step 2. Enable options to wipe your device in case of loss.

Step 3. Avoid open Wi-Fi networks.

Step 4. Use VPN for secure connections if you must use an open Wi-Fi network.

Step 5. Disable Wi-Fi tethering or connection sharing services if not in use.

On iOS, go to Settings > Cellular > Cellular Data Usage. Use sliders to disable any apps that should not be using cellular connections. Turn off Cellular Data if there is no data allowance left in the current period.

If you see unusual amounts of data usage, it could be a sign of malware.

However, unauthorized root access is a different story. Unauthorized root access on an Android device is a risk when users download apps that are not from Google Play. These apps do not properly follow the permissions rules and may elevate permissions without the user’s knowledge or consent. Running a device in Developer mode (used for software and service development and testing) disables most safeguards. On current versions of Android, it takes several steps to enable Developer mode so it’s difficult to do it accidentally.

Jailbreaking an iOS device or rooting an Android device puts the device and its information at much higher risk than with a normally functioning device.

To prevent iOS from tracking your location by Wi-Fi connections:

Go to Settings > Privacy > Location Services > System Services and then turn off Frequent Locations and clear history.

To prevent Android from tracking your location by Wi-Fi connections:

Go to Settings > Personal > Privacy and Safety > Location > Locating Method > GPS only.

Third-party apps can be used to perform location tracking without the authorization of the device user. These apps are marketed to parents and organizations who want to keep track of individuals.

Malicious apps with this feature could be installed by a user who does not use Google Play or the App Store to install apps.

Some apps can be installed on iOS without physical access to the device: just the Apple ID and password are needed.

Malicious apps with this feature could be installed by a user who does not use Google Play or the App Store.

To reduce CPU, memory, and storage usage:

Uninstall apps that are not needed.

Configure apps to receive updates only via Wi-Fi.

Turn off background updates.

To see real-time resource usage by app for iOS, download the latest version of Xcode from the Apple Developer website and use its Instruments app. Learn more at http://apple.stackexchange.com/questions/71237/how-to-identify-cpu-and-memory-usage-per-process-on-iphone.

To see real-time resource usage by app for Android, use System Monitor from AndroidPit.com. For additional resource monitoring, see https://www.androidpit.com/best-apps-for-monitoring-system-performance-on-your-android-device.

See the next section, “Tools,” for methods for detecting and blocking malware and hostile apps and processes.

The Zscaler Application Profile (http://zap.zscaler.com/) is a well-regarded tool for evaluating iOS and Android apps. Search for the name of an app and the operating system, and Zscaler checks its database for matches. For example, searching for flashlight iOS came up with five matching apps, four of which had security/privacy risks of 50 or greater (100 being greatest risk, 0 being no risk). Zscaler can also check an app you specify on the App Store or Google Play for risks.

Bitdefender anti-malware offers a free Android app called the Clueful Privacy Advisor through Google Play. Clueful lists apps by potential threat and enables the user to see the permissions for any app.

If the device is not encrypted yet, set up a PIN first. This automatically encrypts the device.

For Android:

Step 1. Make sure Back up my data and Automatic restore are enabled. See the “Backup/Restore” section in this chapter, for additional backup processes.

Step 2. Go to Settings > Personal > Backup and reset > Factory Data Reset.

Step 3. After reviewing the warnings, click Reset Device.

The device will be returned to its factory configuration. All data and device updates will be removed from the device.

To restore data to this device or to a different device, see the “Backup/Restore” section later in this chapter.

For iOS:

Step 1. Install the latest version of iTunes on your host PC or OS X computer.

Step 2. Start iTunes.

Step 3. Connect your device to the computer via the 30-pin or Lightning charge/sync cable. Trust the device or enter a passcode if prompted.

Step 4. Select your device.

Step 5. Back up its contents. See https://support.apple.com/en-us/ht203977 “Make a backup using iTunes.” Be sure to use Transfer Purchases for content purchased from iTunes, the Health & Activity data stored on your device (backup must be encrypted), and start your backup. To learn more about the iOS Health app, see https://support.apple.com/en-us/HT203037.

Step 6. To erase the device, go to Summary > Restore.

Step 7. Click Restore again to erase your device and reload it to its original factory condition.

Use iTunes to restore data afterwards. See https://support.apple.com/en-us/ht2041844.

Step 1. Go to Settings > Device > Applications > Application Manager.

Step 2. Select an app and tap Uninstall.

Step 3. To reinstall the app, go to Google Play and reinstall it.

For iOS:

Step 1. From the apps dialog (home screen), press and hold any app icon until they wriggle.

Step 2. Click the X to remove the app. Click Delete to confirm.

Apps can also be deleted by going to Settings > General > Storage & iCloud Usage > Manage Storage, selecting an app, and then tapping Delete.

To uninstall an iOS app, press the app’s icon, click the X, and confirm deletion. You can reinstall it from the Apple App Store.

To uninstall an app with Windows 10 Mobile, press and hold the app icon, and select Uninstall. You can reinstall the apps with the Windows Store.

The Wifi Analyzer from Farpoint is available from Google Play. It provides monitoring in real time, showing SSID, signal strength, and channel (see Figure 22-25).

For Android:

Go to Settings > Device > Applications > Application manager, select an app, tap Force Stop, and then tap OK.

For iOS:

Press the Home button twice, swipe left to find the preview of the app, and then swipe up on the preview to close it.

iCloud (automatic)

iTunes (requires connection to the host PC or OS X computer)

iCloud is easier, but free iCloud storage is limited to 5GB. To back up an entire device, use iTunes.

Android Cloud backup can back up most features of your smartphone or tablet to Google Drive (the first 15GB of storage is free).

To back up e-mails, contacts, calendar, and apps:

Step 1. Go to Settings.

Step 2. Go to Backup and reset.

Step 3. Turn on Back up my data.

Step 4. Turn on Automatic restore.

Step 5. Select Google account for Backup Account.

Step 6. Go to Settings.

Step 7. Go to Accounts.

Step 8. Select Google.

Step 9. Select Gmail and select the services to back up.

To back up photos and videos to Android Cloud:

Step 1. Start Google Photos (download from Google Play if not installed).

Step 2. Open the menu (it’s the three-line icon at the upper left corner of the app).

Step 3. Sign in if prompted.

Step 4. Go to Settings > Back up & sync > Backup (On).

Step 5. Select whether to back up while charging, back up all photos/videos now, or whether to back up while roaming on cellular.

Use third-party apps to back up SMS messages. To back up all phone contents, use backup services provided by some smartphone vendors or download third-party apps from Google Play.

With Windows Mobile, enable automatic cloud-based backup for settings and app data, enable message sync, and turn on camera upload to OneDrive for photos and videos. For details, see http://windows.microsoft.com/en-us/windows-10/getstarted-back-up-mobile.

A blueprint is the term for actions that will be applied to devices, such as configuration profiles and app installation.

Configuration profiles specify device settings for networks, e-mail servers, and other options.

After these steps are complete, devices can be prepared for use.

To prepare multiple devices at the same time, connect them to USB 2.0 or 3.0 ports on the device, or use hubs or iPad charge/sync carts that are MFi certified (MFi is Apple’s Made for iPhone, Made for iPod, Made for iPad, and AirPlay certification program).

A single device can be prepared and backed up; the backup can be restored to other devices.

The processes can be automated if desired.

Technically speaking, the Google Sync app itself is now restricted to paid users of Google Apps for Work, Education, and Government. Google is now using CardDAV to perform sync for its users of free Gmail, Contacts, Google Calendar, and Chrome services.

When these accounts are set up, CardDAV is configured as part of the setup process.

Step 1. Identify malware symptoms. Use Table 22-4 to identify symptoms.

Step 2. Quarantine infected system. Disconnect the system from wired and wireless networks and suspect any media that has touched the system as being possibly infected.

Step 3. Disable System Restore (in Windows). System Restore has been used by some malware programs to reinfect the system. System Restore is designed to help recover from user error or system crashes, not malware.

Step 4. Remediate infected systems. Use a different system to change passwords for network access, e-commerce, and social media. Back up data in case the system must be reformatted. Check backup for malware before reinstalling it.

a. Update anti-malware software. To update anti-malware on a quarantined system, download offline update files on a different system, burn them to an optical disc and close the disc so it cannot be written to again, or copy them to a USB flash drive and install the updates on the quarantined system.

b. Scan and removal techniques (safe mode, pre-installation environment). If a quarantined system’s antivirus/antimalware cannot be updated, the apps might be themselves infected or blocked by malware. Download the files needed to create a Live CD or USB bootable anti-malware disc or USB drive on a different system.

Step 5. Schedule scans and run updates. If the infection source is unknown, run full scans with both antivirus and anti-malware. If the infection source is known by name, first use a specific removal tool (if available) and follow it up with full scans. Scan with more than one tool to assure the infection is removed.

Step 6. After the system is cleaned, reenable System Restore (the source of the infection, such as email, flash drives, downloaded app, and so on) and create a restore point manually.

Step 7. Educate end users. Discuss principles of avoiding malware infections with end users. If the infection vector (the source of the infection, such as email, flash drives, downloaded app, etc.) is known, discuss it specifically as well as provide general guidance for safe computing (avoiding the use of “orphan” USB flash drives, not opening attachments from unknown sources, using real-time antivirus software, scanning systems weekly, etc.).

Stop errors

BSOD

pin wheel

failure to boot

improper shutdown

spontaneous shutdown/restart

device fails to start/detected

missing DLL

compatibility error

file extension

file association

boot configuration data

DLL

missing operating system

GUI

GRUB

LILO

kernel panic

multiple monitor

BIOS

UEFI

SFC

logs

system recovery options

repair disks

pre-installation environments

MSCONFIG

DEFRAG

REGSVR32

REGEDIT

Safe Mode

command prompt

pop-ups

browser redirection

security alerts

rogue antivirus

spam

file permissions

hijacked e-mail

access denied

invalid certificate (trusted root CA)

antivirus software

anti-malware software

Recovery Console

terminal

Refresh

Reset

malware

System Restore

quarantine

remediate

restore point

scan

end user

system lockout

hard reset

soft reset

factory default

overlimit

pairing

root access

app scanner

factory reset

clean install

Wi-Fi analyzer

Force Stop

cell tower analyzer

iTunes

iCloud

Apple Configurator

Google Sync

OneDrive.

Use Activity Monitor on an OS X system to see how it is using resources.

Start Linux in Recovery or Rescue mode.

Start Windows in Safe mode.

Start OS X using Command+R.

Use Device Manager to see if any devices are unknown, disabled, or can’t start.

Use two displays with Linux, OS X, and Windows and set them up as mirrored or extended desktops.

Use a soft reset/soft restart with an iOS and an Android device.

Install a new app on an iOS and/or Android device. Update it and then delete it.

Check data usage on an iOS and/or Android smartphone.

A. OS X

B. Windows 7

C. Linux

D. Windows 8.1

How would go go about researching this problem?

1. Search online for “A problem has been detected”

2. Go to Linux.org and search for IRQ_NOT_LESS_OR_EQUAL

3. Go to Apple.com and search for IRQ_NOT_LESS_OR_EQUAL

4. Go to Microsoft.com and search for IRQ_NOT_LESS_OR_EQUAL

Which of the following is the most likely solution to the problem?

a. Install an update to OS X

b. Open Device Manager and update a driver

c. Use apt-get to install a Linux update

d. Reinstall the operating system

2. In the following figure, the screen is displaying a spinning wait cursor or pin wheel that indicates that the system is unresponsive. One possible cause for this pin wheel could be that there is less than 10 percent free space left on the system drive. Why would a lack of free space be causing a problem for the system?

A. You are running out of space on the drive and cannot store any more files

B. At least 10 percent free space is needed for a swap file.

C. You do not have enough free space on the drive to upgrade to the latest version of the operating system.

D. Your applications need more space in which to run.

3. How would you try to repair a missing or corrupt BOOTMGR file on a Windows system?

A. Use the System Recovery Options.

B. Use the Advanced Boot Options.

C. Reboot the computer and edit the BIOS startup program.

D. Go to the Internet and download a new BOOTMGR file.

4. Which of the following procedures best describes how to create a dual boot system using Windows 7 and Windows 8.1?

A. Install Windows 7 first, then install Windows 8.1 into a separate partition.

B. Install Windows 8.1 first, then install Windows 7 into a separate partition.

C. It does not matter which you install first.

D. You cannot dual boot these two operating systems.

5. Which of the following is the most common boot loader in current Linux distributions?

A. CRON

B. LILO

C. BCD

D. GRUB

6. Which of the following procedures best describes how to access the special startup modes in OS X?

A. Press Ctrl+R.

B. Press Command+R.

C. Press Ctrl+Alt+Del.

D. Press Alt+F1.

7. If a program that loads automatically during startup is causing problems during startup or shutdown, which Windows utility should be used to diagnose and resolve the problem?

A. BIOS

B. SFC

C. MSCONFIG

D. REGEDIT

8. Your Windows computer has been configured to automatically restart after a system shutdown due to a STOP error. Which of the following menu options best describes how to disable the automatic restart feature?

A. MSCONFIG > Boot > No GUI boot

B. System Properties > Advanced > Startup and Recovery > clear Automatically restart checkbox

C. Drive Properties > General > Disk Cleanup

D. System Properties > System Protection > Create

9. In Windows, how will a non-working device be displayed?

A. In MSCONFIG on the Startup tab, an error message is displayed next to the device.

B. Action Center displays an error message.

C. An error message will be displayed in the System Restore utility.

D. In the Device Manager, the device will be displayed with an exclamation mark inside a yellow triangle.

10. Which of the following statements best describes why a device is listed as Unknown in the Device Manager?

A. There is no installed driver.

B. The device is not functioning.

C. The device has been disabled and is no longer listed.

D. The device has been removed.

11. If a Windows system file is missing or damaged, which utility is used to recover it?

A. Device Manager

B. SFC

C. MSCONFIG

D. Safe Mode

12. Which of the following could be causes of poor system performance on a Windows computer? (Choose all that apply.)

A. The drive containing paging and temporary files is nearly full.

B. Dust and dirt are restricting airflow and the CPU is overheating.

C. Too many services are configured to start automatically during startup.

D. Minimum memory requirements have been met but not exceeded.

13. In Windows, when a file extension is not associated with a program, which of the following occurs?

A. The file will not open.

B. The file will open in Notepad with no formatting.

C. The file will open in Notepad with minimum formatting.

D. The file will open in either Windows Explorer or File Explorer.

14. When a Linux or OS X system crashes as a result of a fatal error in the operating system, it is known as which of the following?

A. A STOP error

B. A fatal error

C. A kernel panic

D. A kernel wipe

15. Match the method for configuring multiple displays with the operating system.

1. System Preferences > Displays

2. Display > Screen Resolution

3. Settings > Display

16. In which of the following locations would you find the log files that Windows creates describing information, warnings, and errors on your system?

A. Device Manager

B. Event Viewer

C. Finder

D. Recovery Environment

17. System Restore is used to do which of the following?

A. Restore the system to its original configuration

B. Remove apps not from Windows Store and reinstall apps that are from Windows Store

C. Use a system image to restore the computer to its original condition

D. Create a restore point with which to restore the computer to an earlier point in time

18. Which Windows utility is used to disable any programs and services that run when the computer boots?

A. REGEDIT

B. MSCONFIG

C. SFC

D. MSINFO32

19. In Windows, if one program stops working after you install or remove another program, you might need to register the .dll or .ocx files for the first program. Which utility should be used to do this?

A. REGSVR32

B. SFC

C. Recovery System

D. Safe Mode

20. In Windows 8/8.1/10, which of the following procedures is used to open Safe Mode? (Choose two.)

A. Press F8 during startup.

B. Press Alt + F1 during startup.

C. Use MSCONFIG, Boot tab.

D. Reboot, hold down the Shift key, and select Restart.

21. Match the following Advanced Boot Options or Startup Settings with the phrase that describes their functions.

Answer Options:

1. You want to determine which device or process is stopping startup.

2. You have just installed new hardware or software and Windows won’t start.

3. You have just upgraded a device driver and Windows won’t start.

4. Configure this setting if you have frequent STOP errors.

5. You have just installed a new video card and Windows won’t start.

22. On an OS X computer, when you reboot and select Internet Recovery from the recovery options, which of the following occurs?

A. The computer’s original operating system reinstalls.

B. The most recent OS X release installs.

C. System fixes and updates are installed.

D. Nothing. You cannot reboot to Internet Recovery.

23. Which of the following procedures best describes how to stop mobile devices from pairing with unknown Bluetooth devices?

A. Use encryption on your mobile devices.

B. Require a device to have the correct code before pairing.

C. Use a VPN whenever possible.

D. Disable Wi-Fi tethering.

24. Which of the following problems might occur when you install third-party apps on a mobile device? (Choose all that apply.)

A. Unexpectedly high resource utilization

B. Unauthorized root access

C. Unauthorized location tracking

D. Unauthorized camera or microphone activation

25. You need to back up 14.5GB of information from an iOS device. Which of the following is the best choice?

A. iCloud

B. iTunes

C. Android Cloud

D. OneDrive

26. You want to prevent an Android smartphone from tracking the user by Wi-Fi connections. Which of the following is the correct command sequence?

A. Settings > Privacy > Location Services > System Services

B. Settings > Network > Wi-Fi > Disabled

C. Settings > Personal > Privacy and Safety > Location > Locating Method > GPS only

D. Settings > Network > Airplane Mode

On a Linux system, which boot options are available when starting in Recovery or Rescue mode?

On an OS X system, did you discover any performance problems when using Activity Monitor?

Did you discover any problem devices with Device Manager? Were you able to resolve the problem? If you discovered problems with unknown devices or devices that can’t start on a laptop that is running a version of Windows that is newer than the version that was originally loaded on the laptop, you might need to download specific driver packs for the laptop and Windows version.

When you installed the app, were you offered an update automatically? If not, check for an update after a week or two.

When you checked data usage, were you near the device’s data plan limit per billing cycle? If so, make sure the user knows when to use Wi-Fi and when to use cellular connections.

2. B. Free space on the system partition is used as a swap file when sufficient RAM is not available. If this is the reason that your system has become unresponsive, you should clear space from the system partition by rebooting the computer to free up temporary files, emptying the Trash, or removing files and storing them on another drive or in the cloud. Upgrading to a newer OS X version can also help to improve responsiveness.

3. A. Use the System Recovery Options and select either the Startup Repair option or open a command prompt and enter bootrec /fixboot. Advanced Boot Options are used to start windows in Safe Mode or other troubleshooting modes. Although a change in the BIOS startup settings to a different startup drive could cause this problem, it isn’t likely. BOOTMGR cannot be downloaded from the Internet.

4. A. You should always install the older operating system first. Thus, you should install Windows 7 first, then install Windows 8.1 into a separate partition.

5. D. GRUB is the most common boot loader in current Linux distributions, while older Linux distributions used LILO. To load Grub, press the Shift key while restarting the system. If you need to repair the system, choose Rescue or Recovery when Grub loads. Cron is a time-based job scheduling utility in Linux computer operating systems. BCD is the boot configuration database used by Windows Vista/7/8/8.1/10.

6. B. Press Command+R as soon as you hear the startup sound. After choosing your language, you will have the option to restore, reinstall, get help, or open the Disk Utility. OS X uses the Command key in place of the Control key used in Windows. Ctrl+Alt+Del displays a menu that includes Task Manager and other options. Alt+F1 opens the Applications menu in Ubuntu or the Start menu in KDE’s K-menu.

7. C. MSCONFIG is a Windows diagnostic tool that allows you to disable and reenable programs and services that automatically load and run during startup. The BIOS (also applies to UEFI firmware) is used to configure basic hardware settings before the OS starts. SFC is the Windows System File Checker. REGEDIT is the Windows Registry editor.

8. B From the Start menu, right-click Computer and select Properties (Windows Vista/7). Press Windows key+X, System (Windows 8/8.1/10). Then click Advanced System Settings. Under Startup and Recovery, select Settings. Under System Failure, clear the Automatically Restart checkbox. The MSCONFIG Boot tab is used to specify startup options such as Safe Boot, boot log, and others (equivalent to selecting options from the Advanced Boot Options menu at startup). The General tab in a drive’s properties shows the file system, drive letter and name, and free/used space. The System Protection tab in System Properties is used for System Restore functions.

9. D. Device Manager reports on the status of all hardware devices on the system. A non-working device will be displayed with a black exclamation mark inside a yellow triangle. Also, when you open the properties of the device, you will see a brief description of the problem on the General tab. MSCONFIG does not list device information. Action Center displays warnings about maintenance and security issues, but not about device drivers. System Restore displays information about device drivers that will be removed or reloaded when a restore point is chosen but it does not display error messages.

10. A. An unknown device does not have a driver installed. Try installing the driver and then reconnecting the device. The device cannot function without a driver. A disabled device is still listed, but it’s displayed with an icon indicating it is disabled. A removed device is also removed from Device Manager.

11. B. SFC checks your system files, locates damaged/corrupted files, and reinstalls replacement files. Device Manager is used to view, manage, and install devices and drivers. MSCONFIG is used to configure Windows startup options. Safe Mode is used to start Windows for troubleshooting.

12. A, B, C, D. The drive containing the paging and temporary files must have at least 10 percent free space; 20 percent free space would be better. If dust and dirt build up around internal components, the CPU and system fans might not be able to adequately circulate the air and dissipate the heat that builds up, so the CPU might overheat. If your system is performing at a low level, you might try increasing the amount of RAM. Generally speaking, more RAM equals better performance. Too many programs and services at start up will slow the startup process and slow down system performance afterward.

13. A. When a file extension is not associated with the file, Windows will not know which application to use to open it. For example, a file with the .docx extension must be opened with Word; it cannot be opened with Excel.

14. C. Kernel panic is when a Linux or OS X system crashes as a result of a fatal error. It is similar to a STOP error in a Windows system. Kernel wipe is not a valid issue with these operating systems.

15. A—1. B—3. C—2.

16. B. The Event Viewer contains the log files that Windows creates to record problems within the system. Device Manager stores information regarding hardware devices and their drivers. Recovery Environment is used in Windows Vista/7/8/8.1/10 to diagnose and repair system failures. Finder is the file manager program in OS X.

17. D. Use the System Restore utility to create restore points before making major changes to your system. Then, if your system has a problem, you can revert to a restore point and your computer will be configured as it was when the restore point was created.

18. B. MSCONFIG is a troubleshooting tool that is used to configure your system startup. You may use it to disable or enable any programs or services that run automatically when the system boots. You may also use it to configure a Normal, Diagnostic, or Selective startup and to configure the order in which multiple operating systems boot. REGEDIT can be used to change all Windows settings, but it is not the preferred tool. SFC is used to replace damaged Windows system files. MSInfo32 is used to display Windows and hardware configuration.

19. A. Use REGSVR32 to register file types. SFC is used to replace damaged Windows system files. Recovery System is not a valid Windows feature. Safe Mode starts Windows with minimal drivers for troubleshooting.

20. C, D. Safe Mode is one of the selections in the Startup Settings menu. In Windows 8/8.1, you should reboot the system, hold down the Shift key, and then select Restart. You can also enter Safe Mode from the MSCOFIG utility on the Boot tab. In previous versions of Windows, you could press F8 when rebooting, but that will not work in Windows 8/8.1.

21.

22. A. Rebooting the computer and selecting Internet Recovery will reinstall the operating system to the state the computer was in when it was new. If you were to select the Recovery System option, you would install the most recent release of the operating system.

23. B. If your mobile devices use Bluetooth, you should configure those devices to request a code from any devices that attempt to pair with them. Encryption, VPN, and disabling tethering are all good security measures but they do not prevent pairing with unknown devices.

24. A, B, C, D. All of these problems could be caused by malicious software that was not downloaded from Google Play or the App Store.

25. B. iTunes is the best choice because it is limited only by available disk space on the iTunes host. iCloud has only 5GB of capacity unless the user has subscribed to a paid data plan. Android Cloud backs up Android devices. OneDrive is a Microsoft product that can be used by OS X and Android devices but requires a free Microsoft account.

26. C. Settings > Personal > Privacy and Safety > Location > Locating Method > GPS only. Settings > Network > Wi-Fi > disabled turns off Wi-Fi. Settings > Privacy > Location Services > System Services > is the correct answer for iOS. Settings > Network > Airplane Mode turns off all radio services.