Recover contacts (email addresses) from 2020 Acronis backup of old Windows 10 computer.

There are two files: abook.sqlite and history.sqlite. If you were using an older version of thunderbird, the files would be abook.mab and history.mab. If in doubt, get them all. Once you have them, respond to this thread for info on inserting into your thunderbird profile.

I finally recovered these files to a portable usb drive: abook.sqlite abook.sqlite-shm abook.sqlite-wal history.sqlite history.sqlite-shm history.sqlite-wal Which are the ones I need and what do I do with them?

I would suggest importing and selecting from a file and then address books.

My approach is to simply paste them into the profile, overlaying the existing files. Do that with thunderbird not running.

Thanks guys for your assistance but because of this so far unsolved problem and other difficulties I have had with the current Tbird version (which have taken up more time that I want to invest), I am going to try another email client. From my perspective, Mozilla has overly complicated a perfectly good program which I had been using for many years.

As the old saying goes: "If it ain't broke, don't fix it."

To paraphrase the old saying, if you like it as it is, don't upgrade.