everyday mac tools

Safe mode on a Mac explained: how to start it and what it tells you

· 6 min read

Safe mode starts your Mac with only what macOS needs to run, so you can tell whether a problem comes from something that loads at startup or from macOS itself. On an Apple silicon Mac you shut down, hold the power button until the startup options appear, pick your disk, then hold Shift and click “Continue in Safe Mode”. On an Intel Mac you restart and hold Shift. If the problem disappears in safe mode, look at what starts with your Mac.

Start safe mode on an Apple silicon Mac

  1. Shut down your Mac. If it won’t shut down normally, press and hold the power button for up to 10 seconds.
  2. Press and hold the power button until “Loading startup options” appears, then let go.
  3. Select your startup disk, usually Macintosh HD.
  4. Press and hold Shift, then click “Continue in Safe Mode”. The Mac restarts.
  5. At the login window, look for red “Safe Boot” text in the upper-right corner, then log in. You might be asked to log in a second time before the Mac finishes starting up.

Start safe mode on an Intel Mac

  1. Turn the Mac on or restart it, then immediately press and hold Shift.
  2. Let go of Shift when the login window appears.
  3. Look for the red “Safe Boot” text in the upper-right corner. It may show on a second login window if you’re asked to log in again.

Macs with Intel chips can’t run macOS 27, so these steps apply to Intel Macs on macOS 26 or earlier. Apple notes that an Intel Mac with a firmware password can’t use safe mode.

Check that you’re really in safe mode

The red text at the login window is the first sign. To confirm once you’re in, hold Option, click the Apple menu and choose System Information. Select Software in the sidebar and look for Boot Mode. In safe mode it reads Safe. In a normal start it reads Normal.

To leave safe mode, choose Restart from the Apple menu and don’t hold any keys. The Mac starts normally.

What safe mode does

Per Apple, safe mode:

  • Stops login items and extensions that macOS doesn’t need, and fonts macOS didn’t install, from loading at startup.
  • Runs a basic check of the startup disk, similar to Disk Utility’s First Aid.
  • Clears some caches, such as font and kernel caches. They rebuild as needed.

It doesn’t touch your files, and it doesn’t reinstall anything. Apple warns that some features may not work as usual in safe mode: video capture, graphics performance, file sharing, Wi-Fi, accessibility features and audio devices, and USB, Thunderbolt or FireWire devices can be affected too. So a screen that redraws slowly is expected. That limit matters when you test: judge the one thing that was broken, not everything.

What the result tells you

Safe mode is a test with two answers.

  • The problem is gone in safe mode. Something that loads at startup or login is the likely cause, or the disk check or cache clearing fixed it. Restart normally and see whether it stays gone. If it returns, the cause is a login item, a background item, an extension or an installed font.
  • The problem is still there. Startup items aren’t responsible. The cause is macOS itself or hardware. Apple’s advice at that point is to reinstall macOS, which keeps your personal files. macOS Recovery explained shows where that option lives, and what a clean install fixes and doesn’t helps you decide how far to go.

If the Mac restarts on its own with a “restarted because of a problem” message, that is a separate case; see your computer was restarted because of a problem. Safe mode is one of the standard steps there. Resetting NVRAM or the SMC is another, and resetting NVRAM and the SMC covers which Macs have either.

When safe mode points at startup items

If the problem vanished in safe mode, narrow it down by removing things one at a time instead of all at once.

  1. Open System Settings, click General, then Login Items & Extensions.
  2. Turn off one app under “Allow in the Background,” or remove one item under “Open at Login.”
  3. Restart normally and use the Mac as you usually do until the problem would have shown up.
  4. If it’s still there, repeat with the next item.

When the problem stops, the last item you changed is the cause. Turn it back on only after the app has an update. Testing from a new user account is another step Apple suggests: if the problem isn’t there, the cause is in your own account’s settings or files.

Before you start

Install macOS and app updates, and unplug devices you don’t need. Apple gives both as steps to take before safe mode, and either can fix a problem without any testing.

Where Foreman fits

Safe mode tells you whether the cause is a startup item. Finding which one is the slow part, because items hide in three places: login items, launch agents and daemons, and background items. Foreman has a Startup Apps page that lists all three grouped by app, with a Disable and an Enable button for each. System daemons need an administrator password to change. How to find out what starts when your Mac starts walks through the same list by hand.

Foreman doesn’t start safe mode, and it can’t tell you whether safe mode will fix the problem; that test is still yours. You can try it free for 24 hours; after that it’s $12, paid once.

Questions

How do I start my Mac in safe mode? On Apple silicon, shut down, hold the power button until “Loading startup options” appears, select your disk, hold Shift and click “Continue in Safe Mode”. On an Intel Mac, restart and hold Shift until the login window shows.

How can I tell if my Mac is in safe mode? Look for red “Safe Boot” text at the upper right of the login window. For a firm answer, hold Option, choose System Information from the Apple menu, select Software and check that Boot Mode reads Safe.

How do I turn safe mode off? Restart the Mac from the Apple menu without holding any keys. It starts normally.

Does safe mode delete anything? No. It doesn’t remove your files or apps. It does clear some system caches, which rebuild by themselves.