Photoscan crashed, or got force quit while shutting down, possibly while still saving my project file. It seems that the project file got corrupted as a result, and won't open anymore.
It would be nice if while saving, Photoscan would keep previous saves up to a certain number so that if the project file was damaged, there would be a recent version to go back to. I only lost today's processing because I have a nightly backup, but I would prefer to have lost only the last job.