External drives · Checking your drive
How do I run First Aid on an external drive in Disk Utility?
Short answer: Open Disk Utility, choose View → Show All Devices, select the drive's volume and click First Aid → Run. For a full check, run it on each volume, then the container, then the device. It repairs file-system errors, not failing hardware.
Open Disk Utility, choose View → Show All Devices, select the external drive's volume in the sidebar and click First Aid, then Run. First Aid checks the volume's structure and repairs the errors it can. Close apps using the drive first.
For the most thorough check, run First Aid in this order: each volume on the drive, then the container (on APFS drives), then the top-level device. Each level checks something different.
What the result means:
- "appears to be OK" — nothing to fix.
- Repaired — run it once more to confirm it now passes.
- Couldn't repair — copy anything important off the drive straight away, then consider erasing it. See what to do if First Aid can't repair it.
First Aid checks the file system, not the hardware. A drive that keeps needing repair may be failing — see checking a drive for errors or health problems.