Skip snapshot checks
Q
How do I get First Aid in Disk Utility to skip checking snapshots on my Time Machine backup volume? byIANWARD
A
You probably don’t want to do that, as they’re the whole reason for checking that volume. When your Time Machine backs up to an APFS volume in Big Sur or Monterey, instead of saving those backups as files stored in folders, it turns them into snapshots. View the contents of your backup volume in the Finder to see them: each backup contains what looks like a disk, the files inside forming the backup.
When First Aid checks a volume, it examines the regular contents of that volume (which for your backup store is precious little), and each of its snapshots. You can run the same check and repair using the command tool relied on by Disk Utility, fsck_apfs, which has an option to skip checking snapshots, but by doing so you defeat the whole purpose of checking a backup volume.
That said, if Disk Utility does find problems with one of those backup snapshots, it can’t repair it, as they’re strictly read-only. So all you can do then is delete that snapshot, and lose the backups it contains. Hopefully Apple will offer a better solution in future.