See if this helps. https://support.mozilla.org/en-US/questions/1161878

This doesn't help b/c it tells me to uninstall TB but when I try to uninstall, I get the message that I have to restart to finish the update. So it is a circular exercise in futility!

From the linked topic: Shut down Thunderbird. Delete the program folder ...

Is this what you did?

Yes, exactly what I did.

What did you do next, and what exactly happened?

TB kept telling me I needed to restart my computer to finish update. I did - multiple times. - each time I hit "Uninstall".

There were 2 versions in my Apps folder. I used uninstall for a version 78.7.1. Each time I tried, it kept giving me the 'Need to restart" message.

After multiple failures, I uninstalled a later version w/o any problems. Still can't uninstall 78.7.1.

So tried to reinstall TB. It downloaded but when I get to the install screen, it says I need to restart to finish the update.

I meant what you did after removing the program folder. After that there should neither be "2 versions in my Apps folder" anymore, nor an old 78.7.1 version.

I guess I don't know how to delete the program folder. You mean from the Local Disk C drive? I was trying to uninstall from the Apps folder.

OK I deleted the TB folder from the C drive. Thank you! I have another problem, though. I keep getting the message that my email doesn't support encrypted passwords & to set it without pw required. Problem is, I have it set that way. I'm also getting the message that gmail has timed out. The help resources do not solve that problem either! I'm a mess!

It is best practice to post one problem per topic. For any other problem you may have, please start a new topic. https://support.mozilla.org/questions/new