“Your computer was restarted because of a problem” appears after a Mac restarts or shuts down unexpectedly. It confirms the unexpected event, but does not identify one root cause or prove a kernel panic or hardware failure. On Apple silicon and Intel-based Macs that can start normally, the safest first action is to install available macOS and app updates, then retest what you were doing when the restart occurred.
The equivalent wording “Your computer shut down because of a problem” can use the same sequence when it follows the same unexpected-shutdown state.
What the alert means and what to observe
Apple lists installed software and connected devices as diagnostic branches for this alert family. Before changing anything, note whether the restart repeats during a particular app or activity. This is an observation prompt, not proof that the app or activity caused the event.
Do not use this guide for a flashing-folder icon, a black screen, the separate USB power warning, or Disk Utility’s separate First Aid failure message. If that message appears, see what to do if Disk Utility separately reports that First Aid has failed.
Update macOS and apps, then retest the trigger
When this applies: The Mac starts normally and can reach Software Update and the App Store.
- Open System Settings > General > Software Update.
- Install any compatible macOS update offered.
- Open App Store > Updates and install available app updates.
- Retest the activity that preceded the unexpected restart.
Expected result: If an update addressed the issue, the restart may not recur during the same test. Risk: Low. Back up before a macOS update when practical. Apple does not specify a rollback for routine updates.
If macOS specifically identifies a suspected app and offers Move to Trash, choose that option, contact the app developer, and check for an updated version. Do not remove unrelated apps merely because this alert appeared. Removing an identified app is a medium-risk step because you may need to reinstall it; documents created with the app are not removed by uninstalling it.
See Apple’s guidance for a Mac that restarted because of a problem for the documented update and app branch.
Test in Safe Mode to isolate startup-loaded software
When this applies: Updates did not stop the restarts, or a software interaction remains plausible. Prerequisite: Know whether the Mac uses Apple silicon or an Intel processor.
- Apple silicon: Shut down the Mac. Hold the power button until startup options appear. Select a volume, hold Shift, then click Continue in Safe Mode.
- Intel: Turn on or restart the Mac, then immediately hold Shift until the login window appears.
- Log in and confirm that Safe Boot appears in the menu bar.
- Use the Mac and retest the usual trigger.
- Restart normally when testing is complete.
Expected result: If the restart does not recur in Safe Mode, that supports a software-isolation branch involving startup-loaded or third-party interactions. It does not conclusively identify one app, login item, extension, or driver. Risk: Low. Restart normally to exit Safe Mode.
Use Apple Safe Mode startup instructions if the startup path does not match your Mac.
Disconnect peripherals and reconnect them one at a time
When this applies: Restarts coincide with a dock, hub, display, drive, printer, charger, or other attached device.
- Shut down the Mac.
- Disconnect peripheral devices such as drives and printers. For a desktop Mac, retain only the display, keyboard, and mouse or trackpad.
- Start the Mac and use it for as long as the restart normally takes to occur.
- If the Mac remains stable, reconnect one device.
- Test after every reconnection.
Expected result: A device that restores the problem is a useful trigger for vendor or service follow-up. Do not reconnect every device at once. Risk: Low; reconnect devices individually after testing. If the restart returns with a USB device or dock, check whether a USB accessory, hub, dock, or its power setup is involved.
Run Apple Diagnostics if the problem continues
When this applies: Peripheral isolation does not stop the issue, or an internal hardware issue is suspected. Install updates if possible. Disconnect external devices except the keyboard, mouse, display, Ethernet if used, and AC power. Place the Mac on a hard, flat, ventilated surface.
- Shut down the Mac.
- Apple silicon: Hold the power button to startup options, release at Options, then hold Command-D until the Mac restarts.
- Intel: Start the Mac and immediately hold D. If that fails, try Option-D.
- Follow the onscreen instructions and connect to Wi-Fi if asked.
- Record every reference code shown.
Expected result: A reported issue or an unresolved reference code is a reason to seek service. A no-issue result does not clear external hardware or macOS software conflicts. In macOS Tahoe 26 and later, Diagnostics can ask you to select a specific diagnostic; earlier versions select automatically. Risk: Low. Exit Diagnostics and restart normally when finished.
Follow Apple Diagnostics instructions for the current on-screen flow and reference-code handling.
When to reinstall macOS or seek service
Seek service rather than continuing repeated tests if the Mac restarts every time it attempts startup, cannot start normally, continues restarting with peripherals removed, Apple Diagnostics reports an issue, or one connected device reproducibly restores the problem.
If updates, Safe Mode testing, and peripheral isolation have not resolved persistent software instability, Apple supports a later Recovery reinstall path.
Warning: Back up important files first. In macOS Recovery, choose Reinstall macOS; do not choose an erase option. Reinstalling macOS without erasing is different from erasing the Mac, which permanently deletes files.
- Back up important files.
- Start macOS Recovery using Apple’s current instructions for your Mac.
- Choose Reinstall macOS.
- Follow the onscreen instructions without erasing the startup disk.
- Retest after installation completes.
Expected result: This may resolve persistent software instability, but it cannot confirm or rule out an accessory or hardware cause. Risk: Medium. The documented reinstall path is non-erasing, but a backup remains important. Erase-and-reinstall is not a routine step for this alert.
Frequently asked questions
Does this alert mean my Mac has a kernel panic?
No. The alert confirms an unexpected restart or shutdown, not one specific cause. Kernel-panic terminology may describe some events, but the alert alone does not establish that diagnosis.
What if the Mac does not restart in Safe Mode?
That supports a software-isolation branch involving startup-loaded or third-party interactions. It does not prove that one particular app, login item, extension, or driver caused the restart.
Can Apple Diagnostics test a dock, USB drive, or external display?
No. Apple Diagnostics does not test external hardware or macOS software conflicts. Use the one-device-at-a-time peripheral test for connected accessories.
Will reinstalling macOS erase my files?
The later path in this guide is Reinstall macOS without choosing an erase option. Back up first. Erasing the Mac is separate and permanently deletes files.