With TB closed, in the current profile, rename abook.* to abook.*.bak, then copy in abook.sqlite from the previous installation. Restart TB and open Personal Address Book. The same method works for history.sqlite (Collected Addresses).

With TB closed, in the current profile, rename abook.* to abook.*.bak, then copy in abook.sqlite from the previous installation. Restart TB and open Personal Address Book. The same method works for history.sqlite (Collected Addresses).

I did it, and now the address book is empty, saying "Contacts from remote address books are not shown until you search. This address book shows contacts only after a search".

And if I try to make a search, nothing happens.

The instructions I gave are exactly what I did myself in a new profile created with 91.0.3. I've no idea why you get a message about remote address books. Perhaps create a new profile from Help/More Troubleshooting, about:profiles, launch the new profile once, then close it (no need to add accounts). Then, open the new profile folder, where you should see a single abook file, abook.sqlite. Copy in abook.sqlite from another source, overwriting the current file, then restart TB in the new profile and open Personal Address Book.

The instructions I gave are exactly what I did myself in a new profile created with 91.0.3. I've no idea why you get a message about remote address books. Perhaps create a new profile from Help/More Troubleshooting, about:profiles, launch the new profile once, then close it (no need to add accounts). Then, open the new profile folder, where you should see a single abook file, abook.sqlite. Copy in abook.sqlite from another source, overwriting the current file, then restart TB in the new profile and open Personal Address Book.

Still not working :( Well, I'll try to do without my old address book. Thank you for your help!

You can import addresses from a previous csv, ldf or vcf file. Do not use old files created in TB profile folder.