macOS · Mac · Everyday fixes

Run First Aid on external drives

External drives fail quietly — files vanish, copies stall. Disk Utility's First Aid catches most problems while they're still fixable.

  • Difficulty Easy
  • Estimated time 10 min
  • Platform macOS
  • Last updated
Run First Aid on external drives — schematic diagram

Before you start

Low risk. This change is reversible — you can return to the previous state without professional help or data loss.

Steps

  1. Open Disk Utility (Cmd + Space → 'Disk Utility'), select the drive in the sidebar and hit First Aid → Start
  2. If it reports errors it can't repair, back up what you can immediately — that drive is on borrowed time
  3. Mac-only drives should be APFS or Mac OS Extended; Windows-shared drives should be exFAT (check under 'Info' after selecting)
  4. Run First Aid monthly on any drive holding important data — ten minutes now beats a data-recovery quote later

How to verify the fix

First Aid completes with The volume appears to be OK (or repairs reported), and files copy without stalling.

If this didn't fix it

First Aid reports errors it can't repair — back up what you can immediately; that drive is on borrowed time.

Next stop: the related fixes below, or start a guided diagnosis.

Related fixes

Still stuck? Diagnose my problem Browse all Mac fixes