2011: Validate Fails on One Machine Only

I'm using ATI Home 2011 to back up a number of machines. After having an issue with one of them not "remembering" about the backups taken, I thought I'd do a little exercise to see exactly what ATI thinks about all my backups.

I booted from the recovery CD and ran Validate against all the backups I currently have stored on my file server. What I found, is a little unnerving, to say the least.

For one machine, and only one machine, all 4 backups I had on the NAS reported as corrupt. This was always within a couple of minutes of starting, and on the "base" of a full + incremental file set. All the backups from the other machines, all reported good.

All backups are done to the same fileserver, and are staggered so that no 2 are ever running at the same time. All machines are running fully up to date 64-bit Windows 7.

Why would all the backups, from a single machine, report corrupt, but all others validate correctly. Does the error message point to what the failure might be, as, of course, the codes are not documented anywhere I can find.

Cheers.