Using Safe mode

You can use Safe mode to force macOS to run a directory check of your boot drive and disable any login items that might be interfering with your system.

If your iMac has an Intel processor, follow these steps:

1. Choose the Shut Down menu item from the Apple () menu to turn off your iMac.
2. Press the Power button to restart the computer.
3. Immediately after you hear the start-up tone, press and hold down the Shift key (and keep holding it down until you see the boot progress indicator).

If your iMac has an Apple processor like the M1, follow these steps:

1. Choose the Shut Down menu item from the Apple () menu to turn off your iMac.
2. Wait 10 seconds, then press and hold the Power button to display the macOS Startup Options screen.
3. Click the entry for your internal drive.
4. Press and hold the Shift key.
5. Click Continue in Safe Mode and release the Shift key.

After macOS boots, you’re in Safe mode (the words Safe Boot appear at the right side of the Finder Menu bar), and you can check the operation of your iMac by using Disk Utility (or a commercial utility application). When you’re ready to return to normal operation, restart your iMac again (this time, without holding down any keys).

Start-up keys

Table 20-1 provides the lowdown on start-up keys, which are available only with Intel iMacs. (iMacs with Apple processors use the macOS Startup Options screen instead, as described in the previous section.) Hold down the indicated key either when you push the Power button or immediately after the screen goes blank during a restart. (As I just mentioned, the Shift key shortcut to Safe mode for Intel iMacs is the exception; you should press it and hold it down after you hear the start-up tone.)

Some of the keys and combinations in Table 20-1 might never be necessary for your machine, but an Apple technician might instruct you to use them.

Step 1: Investigate recent changes

The first step is a simple one that many novice iMac owners forget. Simply retrace your steps and consider what changes you made to your system recently. Here are the most common culprits:

• Did you just finish installing a new application? Try uninstalling it by removing the application directory and any support files it might have added to your system. (And keep your applications current with the most recent patches and updates from the developers’ websites.)
• Did you just apply an update or patch to an application? Uninstall the application, and reinstall it without applying the patch. If your iMac suddenly works again, check the developer’s website, or contact the application’s technical support department to report the problem.
• Did you just update macOS? Updating Monterey can introduce problems in your applications that depend on specific routines and system files. Contact the developer of the application, and look for updated patches that bring your software in line with the latest Monterey updates.
• Did you just make a change in System Preferences? Return the options you changed to their original settings; then consult Chapter 5 for information on what might have gone wrong. (If the setting in question isn’t listed in Chapter 5, consider searching the macOS Help system or the Apple support website for more clues.)
• Did you just connect (or reconnect) an external device? Try unplugging the device and then rebooting to see if the problem disappears. Remember that many peripherals need software drivers to run; without those drivers installed, they don’t work correctly. Check the device’s manual or visit the company’s website to search for software you might need.

If you didn’t make any significant changes to your system before you encountered the problem, proceed to the next step.

Step 2: Run Disk Utility

The next step is to run Disk Utility and use First Aid. The earlier section “Disk repair made easy” shows how to complete this task on your Monterey boot drive.

Step 3: Check your cables

Cables can work themselves loose, and sometimes they fail. Check all the cables to your external devices — make sure that they’re snug — and verify that everything’s plugged in and turned on. (Oh, and don’t forget to check for crimps in your cables or even Fluffy’s teeth marks.)

If a Thunderbolt or USB device acts up, swap cables around to find whether you have a bad one. A faulty cable can have you pulling your hair out in no time.

Step 4: Check your Trash

Check the contents of the Trash to see whether you recently deleted files or folders by accident. Click the Trash icon on the Dock to display the contents. If you deleted something by mistake, right-click the item in the Trash and choose Put Back from the contextual menu.

I know this one from personal experience. A slight miscalculation while selecting files to delete made an application freeze every time I launched it.

Step 5: Check your Internet and network connections

Now that always-on DSL and cable modem connections to the Internet are the norm, don’t forget an obvious problem: Your iMac can’t reach the Internet if your ISP is down or your network is no longer working!

When you’re at home, a quick visual check of your DSL or cable modem usually indicates whether a connection problem exists between your modem and your ISP. My modem has a set of informative activity lights that I always glance at first. If your iMac is connected to the Internet through a larger home or office network, however, and you can’t check the modem visually, you can check your Internet connection by launching Safari and connecting to www.apple.com.

If you can’t reach your network at all, the problem lies in your network hardware or configuration. (In an office environment, your network system administrator will be happy to help you at this point, especially if you’re blood relatives.)

Step 6: Think virus

If you’ve made it to this point, it’s time to run a full virus scan. Make sure that your antivirus application has the latest updated data files. My antivirus application of choice is Avast Security for Mac from Avast Software (www.avast.com). It’s both excellent and free!

If a virus is detected and your antivirus application can’t remove it, try quarantining it instead. This basically disables the virus-ridden application and prevents it from infecting other files.

Step 7: Check your login items

Monterey might encounter problems with applications you’ve marked as login items in System Preferences. Your account’s login items are applications that run automatically every time you log in to your iMac. If one of these login items is to blame for your problems, your iMac will encounter some type of trouble every time you log in. (This is usually the case when you receive an application error message each time you start the computer.)

To check the boot process, it’s time to use that fancy Safe Boot mode I discussed earlier in the chapter. Follow the instructions for starting in Safe mode. Login items are disabled when you’re running in Safe mode, so if your computer starts up without any errors, you know that one or more login items are probably to blame.

If your computer starts without problems in Safe mode, the next step is to check your login items. Restart your iMac and then follow this procedure for each item in the login list:

1. Open System Preferences, click Users & Groups, and then click the Login Items button.

2. Select the first item from the list and remove it.

   You can delete the selected item by clicking the Delete button, which bears a minus sign. (If a recurring error message mentions a specific application that appears in the Login Items list, that’s your likely culprit, so start by deleting that item.)

3. Restart your iMac.

4. If your iMac is still misbehaving, repeat Steps 2 and 3, and disable a new login item.

   When your Mac starts up normally, you have discovered the perpetrator.

5. Delete that application and reinstall it.

   Don’t forget to add back each of the working login items to the Login Items list using the Add button (which carries a plus sign)!

Step 8: Turn off your screen saver

The next step is to turn off your screen saver. This remedy is a long shot, but it isn’t unheard of to discover that a faulty, bug-ridden screen saver has locked up your iMac. If you are running a screen saver other than one from Apple, and your computer never wakes up from Sleep mode or hangs while displaying the screen saver, you’ve found your prime suspect.

Reboot your iMac (if necessary), open System Preferences, click Desktop & Screen Saver, and click the Screen Saver button. Then do one of the following:

• Switch to an Apple screen saver.
• Click the Start After pop-up menu and choose Never.

Step 9: Run System Information

Ouch. You’ve reached the final step, and you still haven’t uncovered the culprit. At this point, you’ve narrowed the possibilities to a serious problem, such as bad hardware or corrupted files in your Monterey System folder. Fortunately, macOS includes the System Information utility, which displays real-time information on the hardware in your system. To start System Information, follow these steps:

1. Choose About This Mac from the Apple () menu.
2. Click the System Report button.
3. Click each of the Hardware categories in turn, double-checking to make sure everything looks okay.

You don’t have to understand all the technical hieroglyphics. If a Hardware category doesn’t return what you expect or displays an error message, though, that’s suspicious. (If your iMac doesn’t have a specific type of hardware onboard — such as an optical drive — you won’t see information in that category.)

The Diagnostics category shows whether your iMac passed the Power On self-test.