That’ll teach me to recommend Time Machine, and occasionally Time Capsule, to everyone around me. It’s entirely possible that my external hard drive is faulty (even though Disk Utility doesn’t see anything wrong with it), but whatever the technical reason, and no matter how valid it may or may not be, the one thing that’s inexcusable is that error message (that I’ve gotten four times in a week): it doesn’t inform me in the least about how the state my backup is in. Is my whole Time Machine screwed up? (Apparently not.) Are the files I modified in the last hour lost for the cause? Or will OS X try to copy them again next time?

Chances are the last possibility is the right one (well… let’s say I hope it is, but I know Apple, and I heard about the silently failing incremental backups from the Backup app), but my data’s integrity absolutely not a place where I should be left guessing.

OS X will forever remain that operating system which had an upgrade release that wiped out all connected external hard drives.