Problem started when for some reason Thunderbird starting Yahoo mail over and over again. I ended up with over 60,000 emails.
Deleting these emails caused Thunderbird to give a not responsive message. So I backed up my address book with Mozbackup. Then I deleted Thunderbird and reinstalled the latest version 78. Unfortunately Thunderbird changed how it stored the address book from map to squit (sic) files. I don't think Mozbackup recognized the change. So when I tried to reinstall my address book, nothing. If the restoration went somewhere, I can't find it. So I deleted Thunderbird 78 and installed Thunderbird 68. But alas no address book. So I deleted Thunderbird 68 and reinstalled 78. I reinstalled all my email settings. No address book. So I did searches for Map files and Squit files. Found some and tried to use the squint files to recreate my address book. Worked to a slight degree though many field were not populated. Tried converting the MAP files to cvs files and importing them to Thunderbird. Again with limited success. Many fields were gibberish but some were populated. Is my address book (actually books) permanently lost or is there a way to get them back? Also any idea why Yahoo mail keeps downloading the some messages again and again?