[theducks]

Originally Posted by bookmole

This was made using the Export function. I have used the Import function to unpack it, which it did (all the books + the db), but then was told Calibre couldn't create the library at the chosen location, and to choose another one.

Which I did - I have put this on my desktop (now OneDrive has been deactivated!) and in Documents.

I do store the backups on a NAS, but it's only used by my and Hubs, and he doesn't use Calibre, so it's pretty safe.

Just flummoxed!

Original setup is still on my Windows7-running laptop, which I wish was still supported.

How long would you expect the Restore function to take for a db of 16,000'ish books?

It is not ALL about how many. It is also how BIG the books are.
Your HD has a Write Rate - the A/V overhead ( Pause that IF you are not doing anything else at the time) IIRC it took me over an hour for a 13G Library with just a over the net copy (~MBps write)