First Aid in Disk Utility checks a drive’s file system and attempts repairs when it finds directory or structure problems. It can help with drives that act strangely, files that will not open, or startup volumes that need repair from Recovery.
This applies to APFS and Mac OS Extended drives on recent macOS versions.
Does This Affect You?
Use First Aid when a drive behaves oddly, apps crash while opening files, an external disk seems unstable, or macOS reports disk-related errors.
Run First Aid Inside macOS
- Open Disk Utility from Spotlight or Applications > Utilities.
- Select the drive or volume in the sidebar. Start with Macintosh HD for the internal volume if you are unsure.
- Click First Aid in the toolbar.
- Click Run.
- Wait while Disk Utility checks the volume and displays progress.
- If it says the volume appears to be OK, no repair was needed.
- If it fixed errors, restart and see whether the problem is resolved.
- Repeat for external drives or other listed volumes as needed.
Run First Aid from macOS Recovery
- Shut down the Mac.
- On Apple Silicon, hold the power button until startup options appear, choose Options, then Continue.
- On Intel, turn on the Mac and immediately hold Command + R.
- Select a user and enter the password if prompted.
- Open Disk Utility from macOS Recovery.
- Select the startup volume and run First Aid.
- Quit Disk Utility and restart when it reports the volume is OK.
First Aid Notes
If Errors Cannot Be Repaired
Back up anything important immediately if the drive is still readable. Then consider erasing/reformatting and restoring from backup, or replacing the drive if failures continue.
Drive Not in Finder
A drive that is missing from Finder may still appear in Disk Utility. If it does not appear in Disk Utility either, suspect the cable, enclosure, port, or hardware.
Not Routine Maintenance
First Aid is for diagnosing problems. Running it on a healthy drive is usually harmless, but it will not clean storage or speed up a crowded Mac.
It Is Not Erase
First Aid repairs file-system structure. It is much gentler than erasing a disk, though any repair on a troubled disk should be preceded by a backup when possible.
Sources
- Apple Support: Use Disk Utility First Aid on Mac
- Apple Support: Repair a disk with Disk Utility
- Apple Support: Start up your Mac in macOS Recovery