I just had the same thing happen after a hard crash.
I was working on a Resolve 17.1.1 project running on Windows and the computer crashed during an edit. I had autosave turned on, but not project backups (silly me, this was a new Windows/Resolve 17 install and just missed that setting).
After the computer restarted, hard crash, I opened Resolve and the project I was working on no longer exists in the project manager. I checked the project's DB location and file structure and it was intact. I then exported the logs and saw the infamous:
"Failed to initialize database"
&
"Project.db @ db17: database disk image is malformed Unable to execute statement"
The "Project.db" file is pretty small'ish about 10MB. Its not a massive project, but it was about a day's worth of work.
I'm guessing this means I'm screwed, eh?
Well, I guess I'm working the weekend now to get these edits out to the directors... ugh!
WeTransfer link of Project.db file & Logs:
https://we.tl/t-XP8VYl80fS