Originally Posted by BetterRed
I've had errors rebuilding an existing database, which didn't occur if I started with an empty database - its happened twice. On both occasions I got all my books back.
That's why I thought it was worth trying, especially on a 61,000 book library.
But you know a lot more about Calibre than me, so I'm happy to defer.
Interesting - I thought that the first thing the restore did was set the database to an empty state. However as you say you have had success with that approach it could definitely be worth trying. It would certainly be a lot less effort if successful.