This could easily a problem if you deal with a few disks containing mirror copies of the archive. Before a disk obviously fails, it already may contain corrupt data. These corrupt data/images may then get copied along onto the upcoming mirror disks.
On the topic of corrupt data:
Is there some software that can quickly confirm the integrity of a collection of NEF files without the need to try to view them all.
I was going through my collection a while back and got back into tagging/keywording what I could reasonably do in a new session.
I noted that some images(only in one directory) had been corrupted. No program would display them as an image nor the preview file(embedded jpg file).
I tracked the corruption of those images down to an issue I had with the docking station when I initially got it and started using it.
On USB3 the docking station would suddenly quit transferring data and hang. (turned out to be a badly made driver for the device).
I initially started to transfer my archive to a new HDD connected via USB3, and the transfer would hang after a short time.
Gave up on that, connected the docking station to USB2 and it would transfer the archive without issue.
Finally go the driver sorted and USB3 would work fine .. but unknown to me in the few attempts I made to transfer the data via USB3 where the transfer quit, the hanging process must have corrupted some of the images.
From memory I think 8 images were lost and I can't figure out a way to recover them(but that's not the issue).
The sudden loss of connection must have caused the loss, as the last written file date of those images corresponds with the time when I got the docking station(and new HDD and started the secondary backup process).
I know you can do a md5 hash checking thingy to compare one archive set compared to another, but this is no good if both archive sets are corrupted in the same way.
Is there a program that can simply scan or check to see if the image file(tiff or NEF) is corrupted in any way.
The only reason I noted those files was that the preview files in that folder weren't displaying at all, so went in to view what those files were.