[asw22]

I did that, and the original library database was "properly" restored, with the same issues as before:

1) I have a list of a dozen books without format...for instance I have a series of 14, for which there are 14 folders in the library including two without format: only two books shown in Calibre, and the two without format also shown?? It totally baffles me!

2) another series of 12, all ok except number 2, which is properly present in the library with its 11 other issues, except this one is not shown by Calibre!

I have no idea what happens...

3) I have many duplicate folders, one complete, one with just the opf. The verification of library seems to identify them, but I seem unable to use the verification process properly: even after 1/2h waiting the process is still non responsive...

I wonder if a interesting way to recreate a library would be to use an improvement to the technique mentioned by Kovid of extracting only books from the source library (which is the case now with the loss of all cover & metadata), but the individual book folders, including cover and metadata, with checking there is a real book inside? Is there already a way to do that?

Thanks to all of you helping me!

asw22