[gandoe]

So, I think I've created my own problem. I had been running Calibre on my desktop system w/no problem; library files (and anything else in the MyDocs folder tree) mirrored monthly to a NAS. My Calibre backups are more sporadic. About 3 months ago, I moved the entire MyDocs folder tree into Microsoft OneDrive; still local on my machine, but also accessible via the web.

About a month ago, I recently purchased a new laptop; and used the same Microsoft credentials to set up, so that the Microsoft OneDrive would then also be sync'd to the laptop.

Well, somehow my versions of the Calibre library got unsync'd because I was in the process of adding some new books, and accidentally added an older book which I knew was already in my library; but never received the relevant Calibre message about combining records.

Short story, it appears that all my books are in the Calibre Library folder tree, but a fair number are not in my Calibre database. Running a Check Library shows some 150 "Extra titles", files in the library without corresponding data base entries.

It is possible that I may have committed a classic "Doh" error...I use both an Onyx Boox eInk and Samsung Tab8 Pro for reading, and in syncing, adding and removing books from either or both devices, I may have accidently "Remove Selected Books" rather that "Remove Matching Files from Device"

I assume I could restore an older backup file, and then simply add back the newer additions; however, my actual Calibre Backups are not very recent; I didn't recognize that the mirrors of the Calibre Library weren't the actual Calibre database files, located in the program files directory. Is there any file locations which might have prior copies of the Calibre database?

Otherwise, does anyone have any suggestions about either somehow restoring a prior copy of the database files (if I can find them) or otherwise adding back all those "Extra titles"?

TIA
Ed