How to Fix a Mac that Keeps Rebooting

Authored by: Support.com Tech Pro Team

1. Introduction

If you've ever experienced a black and grey kernel panic screen, it can be very abrupt and frustrating. When an app has a problem, you may simply see a spinning wheel cursor, but when multiple apps fail - or the operating system fails itself - you may experience a kernel panic.

This guide will take you through some steps that can help you overcome an unexpected kernel panic error. The steps are listed in order, so start with the first one, see if that helps, and then continue with the next one if it doesn't.

What You'll Need:

  • No extra tools or supplies are needed.

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Before You Begin:

Extra instructions.

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macOS kernel panic

2. Force Restart the Mac

If your Mac computer is showing a Kernel Panic screen, is frozen or not responding, you may need to forcefully restart it.

This works nearly the same on any modern Mac, with the difference being whether the Mac has a physical power button on the back of the machine or if it is a MacBook, where the power button is a part of or slightly above the keyboard.

  1. Hold down the Power button on the Mac until it shuts down completely, this may take 5-10 seconds or so.
iMac rear-facing power button.
  1. Wait a few seconds then press the Power button again to boot the Mac.
MacBook power button on the keyboard.

3. Check for Updates

  1. Click the Apple menu, then click onApp Store.
Apple menu with App Store highlighted.
  1. Select Updates on the bar at the top.
App store menu bar with Updates highlighted.
  1. Any pending updates for your Mac will be listed here. Select Update All to apply these updates.

MacBook, MacBook Pro, and MacBook Air must have the power adapter plugged in to automatically download updates.

4. Check Startup Programs

  1. Click on the Apple Menu, then click System Preferences.
Apple menu icon highlighted with menu beneath highlighting the system preferences option.
  1. Choose Users & Groups.
macOS system preferences window with users and groups icon highlighted.
  1. Choose Login Items at the top. Then, choose your username on the left. Then, click the Lock icon at the bottom. You may need to type in your Mac password to unlock this screen.
macOS users and groups window highlighting the login items tab, and the admin account selected.
  1. Look through the list on the right. If you see an item you don't recognize, or an item you don't use frequently, highlight it by clicking its name, then click the Remove – button below to remove it.
macOS users and groups window highlighting the minus button.

5. Reinstall macOS

When you've exhausted all options in trying to fix a major issue with your Mac computer, you may be left with having to reinstall macOS to bring it to its original state it was in out of the box.

Reinstalling macOS will remove all customization, files, and programs on your computer. Make sure you have a recent backup before proceeding.

Back Up All Personal Data

  1. Select Apple Menu > Restart.
macOS Mojave Apple Menu with Restart highlighted.
  1. Immediately after your Mac restarts (some Mac computers play a startup sound), press and hold the command ⌘ and R keys until the Apple logo appears, then release the keys.
Mac keyboard with command and R keys highlighted
  1. Highlight Reinstall macOS, then select Continue.
macOS Utilities with Reinstall macOS and Continue button highlighted
  1. macOS setup will begin. Select Continue.
macOS Install with Continue highlighted.
  1. Select Agree to accept the Terms of Service.
macOS Terms of service with Agree highlighted.
  1. Select Agree to confirm you agree with Terms of Service.
Terms of Service dialog with Agree highlighted.
  1. Choose a Drive to install macOS on and select Install.
macOS install drive selection with drive and Install highlighted.
  1. Install will now start and this will take some time. The computer will reboot during this process.

If the Issue Persists