How to Fix iMac Frozen Issue (5 Tips)

Apple iMacs are reliable computers. But they can run into problems, one of the issues you may occasionally encounter is a frozen screen.

When your iMac freezes, apps are “stuck” on the screen; the mouse refuses to move and the whole computer becomes unresponsive.

The situation varies from case to case, your iMac may freeze up randomly, while running a specific app, or upon startup.

Causes of a frozen iMac can range from glitchy apps, faulty software, and inadequate RAM or hard disk storage.

In this post, we’re going to share with you a few quick tips that could help you get rid of this annoying iMac freezing issue.

If you love your iMac, you should use CleanMyMac — an app that can help you free up tons of space, it also has a dozen super useful tools to keep your iMac in good shape, which would help you stay away from the iMac freezing problem and many other issues.

1. Force Quit Unresponsive Apps

The spinning rainbow pinwheel is usually an indication of the Mac system lagging.

Your iMac can hang up because of a piece of software. If this is the case, use the “Force Quit” function to unfreeze your machine. Force Quit will exit out of certain apps despite their unresponsiveness.

The iMac menu bar includes the Force Quit function. You can also control-click on the app, press Option, and click on Force Quit.

However, in some instances, the mouse may also be frozen and you might not be able to access Force Quit.

If this happens, you can use the keyboard shortcut for Force Quit: Command + Option + ESC. A window will display listing out all active applications.

Select the unresponsive app and then Force Quit in the bottom right corner. The application will close; if not, try to Force Quit out of it again.

Force Quit, however, does not solve the underlying issue; the app may be causing your iMac to freeze.

To determine whether the app itself is faulty, start up the application again.

If the screen freezes and continues to do so while you use this program, you may have to uninstall the app and reinstall it thereafter.

2. Manually Shut Down iMac

In some cases, you may not be able to use the Force Quit option because that macOS is entirely frozen.

The quick force quit doesn’t work, your mouse won’t move either.

Then you will have to manually shut down your iMac. To do so, hold the power button for several seconds until the iMac shuts down.

By pressing the power button — as opposed to just unplugging the cord — the computer can safely restart. If your iMac reboots and functions normally upon restart, the issue may have been a temporary minor glitch.

3. Troubleshoot in Safe Mode

If your iMac continually freezes up during boot, you can operate in Safe Mode to troubleshoot the root issue. To enter Safe mode, turn on your iMac, hold the Shift key until you see the gray Apple logo.

The computer will then operate in Safe Mode. Go to System Preferences > Accounts, you can view the Login Items.

These Login Items are the programs that launch when your iMac starts up.

If, after un-checking all of the programs, the iMac starts up normally, then you can go through the individual programs to identify which is causing the freezing issue.

4. Verify and Repair iMac Disk Errors

A frozen iMac can be also attributed to the Mac hard drive issues, especially if your iMac is loaded with a traditional spinning hard drive (while most modern iMacs are with Fusion Drives or flash storage).

When your Mac hard drive is faulty or under-performing, chances are your overall system performance is going to be taxed.

Fortunately, Disk Utility allows you to verify and repair potential disk issues. Select Disk Utility from Applications. Click on your hard drive.

If your Mac is with OS X Yosemite or earlier, click on the “Verify Disk” button first and then hit the “Repair Disk” button if it finds some issues; If your Mac is with the newest macOS, you won’t see these two buttons, instead, just click “First Aid” to start and the utility will repair the errors it finds.

5. Reset Minimum Fan Speed

smcFanControl is a third-party app that lets you set a minimum speed for built-in fans on Mac.

With this app, you can manually increase your minimum fan speed to make your iMac run cooler.

One of our readers Kelsey contributed this tip which worked well to resolve the iMac freezing issue.

She set up the minimum fan speed by about another 30%.

Note: smcFanControl will not let you set minimum speed to a value below Apple’s defaults, this avoids damaging your machine.

Other Fixes

If your iMac is always frozen on startup, take a look at this video and follow the instructions:

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  • Kelsey

    Had freeze problems and artifacts on the screen on my 2009 imac. Tried antivirus, malware, resets etc. Finally installed smc fan control and set up min. fan speeds about another 30%. Imac always seemed to run hot, now it’s much cooler and no problems for a week now. Thought I would pass this along in hopes it helps someone else.

    • Avatar photo

      Hi Kelsey, thanks for sharing the tip. In general, we wouldn’t recommend Mac users to install fan control apps — for the concern of causing Mac overheating and other potential issues.

    • George

      Thank you Kelsey, your suggestion was an immediate success!!!

    • Christine

      My mid-2009 iMac has been using smc fan control since a “computer repairman” changed out the hard drive and didn’t install a part to regulate the fan speed. It has been hanging up so much lately that I spent a good part of the afternoon looking for a new computer on line. I saw your suggestion here, and it worked! Thank you!