I ran the recently released update, and when I restarted the program, my project had reverted to a three-week old version. All backups are gone.
Coincidentally, the date of the version is the same as the last date I transferred the project to my backup server.
So the cost for “updating” the software appears to be “backdating” my novel. Thanks so much for losing three weeks of my work!
More likely is that it’s looking in the wrong folder for the back ups?
That’s a good suggestion. Do a search of your entire drive (C:) or drives, if you have more than one, for .scriv
That should, I think, find every scrivener project on your computer.
Hmm, just did the update and it opened the version of the novel I was working on last night. I did have a problem earlier in the week when I tried “save as” and messed things up then couldn’t remember where the original file was filed. But once I found it, everything was as I’d left it.
Before installing a new version or messing around with the program, it’s a good idea to just compile what you have into a Word document – just in case. That way if you run into a problem with Scrivener, at least you have a working version in Word.
Wise words. And something you should do at the end of every work day, anyway. 
I think a lot of people fall into the trap of thinking of “save as” in terms of backing up their work. What’s easy to forget is that when you do “Save As”, once the saving is done, you are then editing the newly created project, and not the original. That’s fine, if it’s how you expect it to go, but contrast that with File->Backup->Back up to…, which creates a copy (optionally ZIP compressed) but leaves you in the original project, so that you can continue editing it, leaving the backup’s contents behind for later recovery if needed.
I’m not saying that is what happened, but it might very well save someone from panicking under similar circumstances.
To sum up:
Save As = create copy, and EDIT THAT COPY
File->Backup->Backup to = create copy, and continue editing the original.
Thanks. That helps. I’ve been trying “save as” when I probably just need a back up file. When I start a new round of rewrites, I like to have a back up point, just in case the rewrite turns out worse rather than better.