Occasionally, your Mac may restart or shutdown unexpectedly. You might see a message like the one above telling you that your Mac had to restart because of a problem. In this article, we will discuss what can cause your Mac to shutdown or restart and what you can do to fix the problem.
If you are having a problem with your Mac freezing and not responding, see our articles:
If you have an app that keeps crashing, see:
- What to do if Mail or other Apps Quit Unexpectedly on Mac
- Safari Isn’t Responding, Keeps Crashing or Freezing, Fix
- Mail Keeps Crashing on Mac
What is Kernel Panic
A kernel panic happens as the result of your Mac shutting itself down in response to a fatal error. Your computer shuts down either because it can’t continue to run (or start up) or continuing would pose a risk of data loss.
Find the Cause of the Problem
When your Mac restarts unexpectedly, it is usually a software problem or a problem with peripheral devices.
- Install any available software updates: macOS, built-in and App Store apps.
- Check third-party apps. You may have seen a pop-up message on your Mac about an app suspected of causing the crash. If you see such a message, click Move to Trash, then check the developers website to see if an updated version of the app is available.
- Boot your Mac in Safe Mode. Using Safe Mode can help you identify the cause of the problem.
- Use crash reports to help troubleshoot the issue.
If you weren’t able to find a software cause for your Mac’s issues, you will want to first look at your connected peripheral devices.
- Shutdown your Mac. Go to Apple menu > Shut Down.
- Disconnect all of your peripheral devices. This includes:
- External hard drives.
- External monitors.
- Anything else connected via USB.
- Leave your mouse and keyboard connected.
- Power on your Mac. You will want to use it long enough to see if it crashes.
If Your Mac Doesn’t Crash with No Peripherals Connected
If this is your situation, you will need to figure out which peripheral is causing the problem. Reconnect one at a time to see if a crash occurs.
If Your Mac Crashes with No Peripherals Connected
Check RAM and Third-Party Hardware
You will want to check your computer’s RAM and any third-party hardware that has been installed. This only really applies if you (or someone else) has installed RAM or other hardware, such as a hard disk. If you have installed anything, check that it is compatible and installed correctly.
Using this tool can help diagnose hardware problems.
- Disconnected all external peripherals from your MacBook except your mouse and power connection.
- Place your Mac on a hard surface.
- Turn off your Mac by going to the Apple menu > Shut Down.
- Turn on your Mac and immediately press and hold the D key. Keep holding the D key until you see the language screen.
- Select your language.
- Your Mac will perform the diagnostics. It will take a few minutes to complete. If your Mac finds any problems, the reports and possible solutions will be reported. The report will reveal if the fan and temperature sensors are working correctly.
If you haven’t found the source of your Mac’s kernel panic issues, you may want to reinstall macOS.
Reinstalling will erase your disk! You must make a backup before reinstalling macOS.
- Back up your Mac using Time Machine.
- Restart your Mac in Recovery Mode:
- Power on your Mac. Immediately hold down 2 keys: Command (⌘) and R.
- Release when the Apple logo appears.
- Choose Reinstall macOS [Big Sur]. Then click Continue. Follow onscreen instructions. Note: if you choose to Reinstall from Time Machine Backup, you may end up with the exact same problem. That is why you are installing a fresh version of macOS.
- Recover your data from Time Machine. For any third-party apps, we suggest downloading the latest version from the developer’s website, in case one of these apps was causing your overheating problems.
- Connect your backup disk.
- Open a Finder window. From the menu bar at the top of your screen, select Go, then Utilities.
- Double-click on Migration Assistant in the Finder window.
- Choose to transfer from a Time Machine backup. Click Continue.
- Select the Time Machine backup you want to use. Click Continue.
- Select the information you want to transfer. Click Continue. If you are transferring a large amount of data, this could take hours to complete.
If you weren’t able to identify and solve the issue, you may want to contact Apple Support for more assistance.