Time Machine is very boolean in it’s operation.  It either was successful or failed.  So if there is a single file that it can’t backup, it aborts it’s current backup, and shuts down until the next backup cycle.  This isn’t exactly an optimal solution.  Other Backup software (eg Retrospect) will log an error on a particular file, but continue with the current backup cycle, until done.

Time Machine does not have any built-in mechanism to verify a set of backups as being valid. That’s one issue with Time Machine, being consumer orientated instead of enterprise…

Sure, you could perform a Disk Repair in Disk Utility, but that doesn’t validate the Time Machine backup data.  That instead will verify the structure and integrity of the backup disk. (Of course, Disk Warrior verifies / repairs in a complementary manner).

The only way that I see that you could verify the data in the backup is to do a full restore.

Well, I have just learned that Time Machine claims to have a verification method, if you are using a Time Capsule.  Option-Click on the Time Machine Menu Extra, and you will see (starting with 10.64) a option called Verify Backups.  This Apple Technote(HT4076) discusses the process, and it is simply running a Disk Utility / Verify Disk on the Time Capsule disk image.  This does not necessarily verify the data was accurately backed up, but verifies the integrity of the Disk Image.

So, it doesn’t really verify your backup data…  It’s verifying the backup file’s integrity…

So at this point, I still have not found a reliable method to verify Time Machine Backups….