A frozen Mac is a rare occurrence, but Macs (like all computers) run in cycles, and sometimes the software gets stuck in a loop. When this happens you may find an app, or the whole of macOS, becomes unresponsive. Learning what to do with a frozen Mac will make you a happier Apple owner.
In this feature we look at what to do with an unresponsive Mac. Follow the steps in this feature to get your Mac unstuck, and working again. Read next: 10 steps to take when your Mac won't start up
Is the problem a single app, or the entire OS?
The first job is to determine whether the whole of macOS - a smart, modern operating system that manages the memory used by apps - is affected, or just one app.
For the most part, if a single application is the problem (typically because it's stuck in a loop and taking up too much memory) you'll be able to tell easily: you'll get an alert (something like the one pictured below) informing you that the app quit unexpectedly. If the Mac locks up without any alert, on the other hand, it's likely that the problem lies with the OS.
We'll deal with OS problems shortly, but if it's just an app causing the issue, you have two main options:
- Click Reopen to start the app up again, and send a report to Apple.
- Click OK to dismiss the alert window.
Stop sending crash reports to Apple
By default, macOS sends a crash report to Apple whenever an application crashes. Apple uses this data to manage development of macOS and provide a more stable operating system (and more stable apps) in the future.
As an aside, if you're not keen on sending app crash data to Apple, you can turn off the automatic report functionality in System Preferences:
- Open System Preferences.
- Click Security & Privacy.
- Select the Privacy pane in the top bar, then click Diagnostics & Usage in the list on the left.
- Click the lock icon in the lower-left of the window to allow changes, and enter your admin password.
- Untick 'Send diagnostic & usage data to Apple' and 'Share crash data with app developers'.
- Click the lock icon again to prevent further changes, then close System Preferences.
Now when an Apple crashes you'll get a Reopen and Report button. Clicking Report will send a report to Apple; clicking Reopen will re-open the program.
What to do if an app freezes
Quitting and restarting the app is the best way for macOS to handle a crash.
A rarer - but also more annoying - problem is if an app simply ceases to function. Often you'll spot this because the app's menus and icons are unresponsive, and you may see the rainbow wheel, also known as the spinning wait cursor. It's also called the 'spinning beach ball', the 'spinning pizza of death' or just SPOD.
Here's what to do if you encounter a frozen app:
- Switch to another area of macOS. Click on another app window, or the desktop. Alternatively, press Command-Tab to switch to another app.
- Control-click the app icon in the dock.
- Hold Option (Quit in the menu will change to Force Quit).
- Select Force Quit.
The app will close down instantly (or almost instantly).
There are other ways to force an app to quit. If the dock is unresponsive, press Command-Option-Esc to open the Force Quit Applications window. Choose an app from the list, and click Force Quit.
For more on force-quitting, take a look at How to force-quit on a Mac and close programs that aren't responding
What to do if macOS itself is frozen (or if an app refuses to force quit)
If you cannot force-quit an app, or if macOS is completely unresponsive, follow these steps in order:
- Open the Apple menu at the top left of the screen, then select Restart and click Restart.
- If you cannot interact with the Apple menu, press Command-Control-Eject. This instructs macOS to restart immediately.
- If that doesn't work, press and hold the Power button on your Mac until it switches off. Press and release the power button to turn it back on again.
When you restart you may find the file you were working on is damaged or corrupted. You should try to recover what you can from it, and transfer any contents to a new file (then delete the file). Read next: How to fix and diagnose performance issues on a Mac
Finding the source of the problem
You should investigate the cause of the crash. If you encounter frequent freezes, check the following:
- Check you've got enough free hard drive space in macOS. (See also How to make more space on Mac.)
- Check for any uninstalled updates in the Mac App Store, and make sure macOS is up to date.
- Update apps installed outside of the App Store manually. Most apps have a 'Check for updates' feature.
- If you're encountering frequent crashes and freezes, you should update your software and then disconnect all your peripherals. Re-attach them one at a time to see if one of them is causing the problem.
- Disable plug-ins. If you use apps with plug-ins, you should disable (or remove) them to discover if they are causing problems.
- Use a Safe Boot by holding down the Shift key while starting up your Mac. This launches macOS without any additional processes and runs clean-up scripts.
- Use Disk Utility's Repair Disk function to clean up any problems with your hard drive.
- Run Apple Hardware Test. This is a special utility from the Apple Support Site that detects problems on your Mac.
Could the problem be a virus or other malware attack?
Scam websites, such as ones using the attack known as 'safari-get', have been known to load malware on to visiting Macs that causes them to open huge numbers of draft emails or iTunes windows, overloading the system memory and causing a lock-up.