What does safe mode do?
Safe mode prevents certain software from loading as your Mac starts up. This includes login items, system extensions that aren't required by macOS and fonts that weren't installed by macOS.
It also performs a basic check of your startup disk, similar to the more comprehensive check performed by the First Aid feature of Disk Utility.
And it clears some system caches, including font caches and the kernel cache. These are automatically created again as needed.
Before using safe mode
If possible, update macOS and your apps before using safe mode. This is more likely than any other step to resolve the kind of software issue that safe mode can help identify. If necessary, you can start up in safe mode and then update your software.
- Install the latest macOS updates.
- Install the latest updates for your third-party apps. If you have the app from the App Store, click the Updates tab in the App Store to check for updates. Or get the updates directly from the app developer or their website.
To ensure none of your connected peripherals and accessories are at fault, test again after unplugging them from your Mac, including printers, drives, USB hubs and other non-essential devices.
Start up in safe mode
Find out whether you're using a Mac with Apple silicon, then follow the appropriate steps.
If you’re using a Mac with Apple silicon
- Shut down your Mac.
- Press and hold the power button on your Mac. As you continue to hold the power button, your Mac turns on and loads startup options. When you see Options, release the power button.
- Select your startup disk. It's called Macintosh HD unless you've changed its name.
- Press and hold the Shift key, then click the “Continue in Safe Mode” button below your startup disk.
- Log in to your Mac. You may be asked to log in again.
If you’re using an Intel-based Mac
If you're not using a Mac with Apple silicon, you're using an Intel-based Mac.
- Turn on or restart your Mac, then immediately press and hold the Shift key as your Mac starts up.
- Release the key when you see the login window, then log in to your Mac.
- You may be asked to log in again. On either the first or second login window, you should see "Safe Boot" in the top right-hand corner of the window. If you can't start up in safe mode, make sure that your Mac isn't using a firmware password.
Test in safe mode
Follow these steps after starting up in safe mode. Some features may not work in safe mode, affecting video capture, graphics performance, file sharing, Wi-Fi, accessibility, audio devices and devices connected via USB, Thunderbolt or FireWire.
If the issue continues in safe mode
If the issue continues in safe mode, the easiest and most likely solution is to reinstall macOS. Reinstalling macOS doesn't remove your personal files, so you can do it whenever you need to.
If the issue doesn't continue in safe mode
Leave safe mode by restarting your Mac normally, then try to reproduce the issue. If the issue doesn't return, it may have been resolved by the other things that safe mode did at startup, such as checking your disk and clearing caches.
If the issue returns, it is caused by a login item or other software that safe mode prevents from loading at startup. In that case, remove login items to find out whether a login item is at fault.
If a login item is not at fault, your old user account may contain other software that is incompatible, including certain software that loads at startup. To confirm this, you can add a user account in Users & Groups settings, then log in to that account and test again. The new account won't have the same settings as your old account, but you can create those settings again.
If nothing else works, reinstall macOS. Reinstalling macOS doesn't remove your personal files, so you can do it whenever you need to.
If you still can't resolve the issue and need help, please contact Apple Support.