Hi Kovid and thanks for such a prompt reply! I'm very impressed (as I am with your CV which I read yesterday!).
I did the backup like that - it, and the restore, took ages so I'm not sure what happened. It was a clean restore and I'm not game to run it again in case I get duplicates of everything, which would be even more of a pain to fix. Mind you, as a very senior Senior Citizen, anything could have happened, but I have been using Calibre for quite a few years now.
Anyway, I guess I'll just work my way through it. I've already found a number of series where I'm missing the latest addition to it, so it's not hurting me to update. I thought there might be an easy answer.
I really appreciate your prompt response though. Cheers, Colleen