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How to Fix Time Machine File system verify or repair failed.:(-69845)?

Time Machine suddenly became read-only after restoring one of the earliest files in the list. Disk utility returned; Repairing file system. Volume is already unmounted. Performing fsck_apfs -y -x /dev/rdisk6s1 Checking the container superblock. Checking the space manager. Checking the space manager free queue trees. Checking the object map. error: (oid 0x14a901) om: btn: invalid o_subtype (0xf, expected 0xb) Object map is invalid. The volume /dev/rdisk6s1 could not be verified completely. File system check exit code is 8. Restoring the original state was found as unmounted. File system verify or repair failed. : (-69845) Operation failed…

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iBoysoft author Eudora Liu

Eudora Liu

Answered on Tuesday, January 27, 2026

When your Disk Utility reports File system verify or repair failed.: (-69845), you may fail to perform file system verification and receive File system check exit code is 8.

File system verify or repair failed.: (-69845) indicates your files system on the drive has been corrupted. This error may happen on an internal or external hard drive on a Mac running any version of macOS.

To fix File system check exit code is 8, it's recommended to go through the following quick solutions.

  • Plug the drive into another PC
  • Use another USB cable
  • Unplug the drive and replug it into a different port

If these fixes don't work, continue with the other solutions below and rerun First Aid until the error has been fixed.

  1. Restart your Mac
  2. Reformat your external hard drive in Disk Utility
  3. Replace it or send it to repair

You may lose data when you format your external hard drive, so I advise you to back up your data. You can use iBoysoft Data Recovery for Mac to get back your corrupted files before you start.

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