Ever since my disastrous problems with the previous laptop constantly crashing hard drives, I've been trying really hard to make sure I have relatively recent backups of my current system. Yesterday, I realized it was a month since I'd backed up my email, and figured I should update that. I plugged in the backup drive... and promptly copied the old version onto the laptop, rather than the other way around.
Intelligence is highly overrated.
If you've sent me anything in the past month that I had not responded to, you probably aren't going to get an answer now. So sorry! I've now learned to change the name of the backup file so it is more obvious which one is which. I did look at the path names, but the string is so long I couldn't see the beginning of it, which is what included the drive designation. I did realize the error as soon as it started copying, but the "cancel" option wasn't as helpful as I'd hoped; the transfer stopped, but apparently Windows deletes the original file before moving the new one over and the delete had already taken place.
I would try to blame the head cold/sinus infection for my befuddlement, but sadly, I really don't think that had anything to do with this particular act of genius.