Just wanted to go on record. If you’re upgrading your Mac this weekend, you might want to turn FileVault off before doing so.
Fortunately, I backed stuff up before the install, and won’t be much hurt except for the aggravation. Nonetheless, it’s annoying. At this point I’d say it’s unlikely that I’ll turn FV back on when I get the laptop running again. Let’s just say I like the idea better than I like the implementation.