Occasionally, Windows decides that my very large NTFS drive is "dirty" and needs to be repaired. It does so successfully, but the experience always makes me uncomfortable—are all of my files really still intact? Were any of them modified or deleted?

The files on this drive are backed up once every few days, so I'm not concerned about actually losing (much) data. However, I don't keep old backups indefinitely, so I'd hate for the originals to get silently corrupted without my knowledge.

Short of comparing/checksumming every file on the disk against my backup copy (which would take days to complete), is there any way to check for file corruption? Is it possible to see what files or directories were modified in the Windows repair, so I could just inspect those?

Note: I do not believe the drive is failing. These repairs usually occur after sudden shutdowns, or when software on my Mac and Windows partitions doesn't want to play nicely together.

  • "is there any way to check for damage?" - This is what the S.M.A.R.T data is used to determine. – Ramhound Sep 15 '17 at 16:58
  • Any drive that behaves as you have described, and does it more than once should be considered defective, and ought to be replaced very soon. – the original mike western Sep 15 '17 at 17:05
  • @Ramhound S.M.A.R.T is fine. It's not physical "damage" I'm concerned about; I really should have said "corruption". – Wowfunhappy Sep 15 '17 at 19:00
  • What does physical damage have to do with my comment? Data corruption, unless you have checksums of every file in their valid state, you can't check for data corruption. – Ramhound Sep 15 '17 at 20:01
  • @Ramhound What I really want to know is what files/directories were "touched" by the windows repair, so I can just verify those checksums as opposed to the entire drive. If this is completely impossible because of how the repair works, that would be an acceptable answer, along with whether I have reason to be concerned by the repair. – Wowfunhappy Sep 16 '17 at 15:55

If you are doing incremental backups, you should be able see if existing files are the same on the disk and in the backup.

If a non-updated file suddenly came up as different in size or date or even as missing, then the disk was damaged and these files need to be restored from backup.

For files that have the same attributes, you may assume that they were not damaged, with a very high probability of being correct.

No guarantees ever exist, so it might be a good idea to, very infrequently, put one backup aside for longer-term storage. This would happen naturally whenever you buy a new backup disk.

On the other hand, be very careful if your backup ever comes up with a disk error. I would advise to have more than one backup media, in rotation.

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