Disk Utility can find and repair errors related to the formatting and directory structure of a Mac disk. Errors can lead to unexpected behaviour when you're using your Mac, and significant errors may even prevent your Mac from starting up completely.
Before proceeding, make sure you have a current backup of your Mac in case you need to recover damaged files or Disk Utility finds errors it can't repair.
Open Disk Utility
In general, you can just open Disk Utility from the Utilities folder of your Applications folder. However, if your Mac doesn't start up completely or you want to repair the disk your Mac starts up from, open Disk Utility from macOS Recovery:
- Determine whether you're using a Mac with Apple Silicon, then follow the appropriate steps:
- Apple Silicon: Turn on your Mac and continue to press and hold the power button until you see the startup options window. Click the gear icon labelled Options, then click Continue.
- Intel processor: Turn on your Mac, then immediately press and hold Command (⌘) and R until you see an Apple logo or a different image.
- You may be asked to select a user you know the password for. Select the user, then click Next and enter their administrator password.
- From the utilities window in macOS Recovery, select Disk Utility and click Continue.
Select your disk in Disk Utility
Choose View > Show All Devices (if available) from the menu bar or toolbar in Disk Utility.
The sidebar in Disk Utility should now show each available disk or other storage device, starting with your startup disk. And beneath each disk you should see any containers and volumes on that disk. Can't see your disk?
In this example, the startup disk (APPLE SSD) has one container and two volumes (Macintosh HD, Macintosh HD - Data). Your disk may not have a container and it may have a different number of volumes.
Repair volumes, then containers, then disks
For each disk you're repairing, start by selecting the last volume on that disk, then click the First Aid button or tab.
In this example, the last volume on the disk is Macintosh HD - Data.
Click Run to start checking the selected volume for errors.
- If there is no Run button, click the Repair Disk button instead.
- If the button is dimmed and you can't click it, skip this step for the disk, container or volume you selected.
- If you're asked for a password to unlock the disk, enter your administrator password.
After Disk Utility has finished checking the volume, select the next item above it in the sidebar, then run First Aid again. Keep moving up the list, running First Aid for each volume on the disk, then each container on the disk, then finally the disk itself.
The order of repair in this example was Macintosh HD - Data, then Macintosh HD, then Container disk4 and then APPLE SSD.
When it's finished, exit Disk Utility. If you used Disk Utility from macOS Recovery, you can now restart your Mac: choose Apple menu > Restart.
If Disk Utility found errors that it can't repair
If Disk Utility found errors that it could not repair, use Disk Utility to erase (format) your disk.
If your disk doesn’t appear in Disk Utility
If Disk Utility can't see your disk, it also can't see any containers or volumes on that disk. In this case, follow these steps:
- Shut down your Mac, then unplug all non-essential devices from your Mac.
- If you're repairing an external drive, make sure it's connected directly to your Mac using a cable that you know is working correctly. Then turn the drive off and back on again.
- If your disk still doesn't appear in Disk Utility, your Mac may need servicing. If you need help, please contact Apple Support.