[manawydan]

I'd like to add my question here because I think it is a similar problem.

My metadata.db got corrupted and the programme did no open but just tried to and then simply crashed.
I copied a backup db into the Library folder instead of the corrupted one and Calibre opens.

My problem is now that I have a db that does not contain the added books after the last backup. The books however are in the Library folder.
Since the db ist big and there have always been problems with running maintenance I am not sure if I can run it wihtout crashing.

Anyway, I have no idea what would be the best solution anyway.
Simply adding the books again? I took copies and put them into a different directory so I can handle this like new additions from directory.

But will this overwrite the folders and files in the library, will it create duplicates or will Calibre just "update" metadata respectively add entries to the db?

P.S. As I thought - maintenance is not possible, Calibre crashes.