Allow me to elaborate. I was moving model files from a local computer into a networked RAID, and in my half-asleep stupor, this is what I did:

move /models/blob.3dm /raid/models/blob.3dm

That worked fine, but when I did

move /models/block.3dm /raid/models.blob.3dm

It deleted my original file, but failed to move it to the new location because I had accidentally used the filename from the first move. Since the file already exists, it fails, but it has already removed the file from its original location by that point, so the file simply vanishes.