Fix Disk Utility First Aid Failed on APFS Volume in macOS

Symptoms

When running First Aid on an APFS volume in Disk Utility, users may encounter one or more of the following errors:

• “First Aid process has failed. Unable to repair volume.”
• “Operation returned error: -69845 (File system verify or repair failed)”
• “The volume could not be repaired because the volume is in use.”
• Disk Utility stalls or freezes during verification.
• APFS container shows as “unmounted” or “offline” after attempted repair.

Root Causes

The failure typically occurs due to:

1. Volume in use: The APFS volume is mounted and actively used by the system, preventing exclusive access.
2. Corrupted APFS metadata: File system structures (e.g., object map, checkpoint) are damaged.
3. Disk queue issues: Pending I/O operations block repair tools.
4. macOS bugs: Known issues in certain macOS versions (e.g., 10.15 Catalina, 11 Big Sur) with APFS repair.
5. Hardware issues: Failing SSD or SATA cable causing read/write errors.

Step-by-step Fix

Method 1: Repair via Terminal in Recovery Mode

1. Restart your Mac and hold Command+R immediately to enter macOS Recovery.
2. From the Utilities menu, select Terminal.
3. Type diskutil list and press Enter to identify the APFS container (e.g., disk2s1).
4. Run diskutil verifyVolume /dev/disk2s1 (replace with your volume identifier).
5. If errors are found, run diskutil repairVolume /dev/disk2s1.
6. If the volume is locked, first unmount it: diskutil unmount force /dev/disk2s1.
7. After repair, exit Terminal and restart normally.

Method 2: Use fsck_apfs with Force Flag

1. Boot into Recovery Mode as above.
2. Open Terminal and identify the disk: diskutil list.
3. Unmount the volume: diskutil unmount force /dev/disk2s1.
4. Run fsck_apfs -y -l -S /dev/disk2s1 (the -y flag answers yes to all prompts, -l enables live repair, -S skips snapshots).
5. If that fails, try fsck_apfs -y -n /dev/disk2s1 (non-interactive mode).
6. Reboot after completion.

Method 3: Safe Mode and Re-run First Aid

1. Restart and hold Shift to boot into Safe Mode.
2. Open Disk Utility and run First Aid on the APFS volume.
3. If successful, restart normally.

Alternative Fixes

• Use Disk Utility on another Mac: Connect the drive via USB or Thunderbolt to a different Mac and run First Aid.
• Third-party tools: Consider DiskWarrior or Drive Genius for advanced APFS repair.
• Backup and reformat: If repair fails, back up data using Target Disk Mode or data recovery software, then erase and reformat the APFS volume.

Prevention

• Always keep a current backup (Time Machine or clone).
• Update macOS to the latest version to avoid known APFS bugs.
• Avoid force-quitting Disk Utility or interrupting repair processes.
• Regularly run First Aid (monthly) to catch issues early.
• Monitor disk health with smartctl or System Information > Storage > S.M.A.R.T. status.

If none of these steps resolve the issue, the drive may be failing. Replace the drive and restore from backup.