I got the error asking if I wanted to rebuild my Calibre database... I said Yes.
I had 13,000+ books cataloged. Now I have 810. I am using version 2.0 (I know there is an update, just haven't gotten around to installing it.) I am running 64-bit Calibra on a Windows 8.1 laptop. My Calibre folder lives on an external hard drive. I would add that I have added several custom columns to Calibre, all of which are still there.
I still seem to have all the folders in my Calibre folder, and I see the following files:
.driveinfo.calibre
.metadata.calibre
metadata.db
metadata_db_prefs_backup.json (which appears to be editable with a text editor)
metadata_pre_restore.db
Short of starting all over with a totally new database and adding all the books from my Calibre folder back in, is there a way to get back to where I was.

