Then when I opened Buzz, it told me my Polac VST loader is old. Oh well, I thought, so I closed Buzz, deleted all the Polac VST loader files and re-extracted the latest loader.
I started Buzz again. Opened the file I was working on last night.
Sequence view - empty.
Patterns - empty.
Wavetable - empty.
I noticed some of the machines were unplugged.
I opened the auto-backup file. Same thing there.

What happened?
Is there any way at all to rescue this song, or should I just delete the file and forget about it?
EDIT: Problem solved! There were a bunch of Bigyo effect machines in the generators folder in the buzzmachines pack. So...downloaders beware!