Day two, same thing. I lost everything: all of the gmail previously downloaded and archived, and it asks me to set up email accounts, like nothing ever happened. Maybe I should trash Thunderbird and reinstall, try one more time? If this happened to anyone who resolved it, please help. Or please recommend a competent email account provider. Gmail is becoming awful.

Okay, so I trashed the downloaded Thunderbird, downloaded again and now things are worse. Google is forcing you to get codes on a phone even with oauth. At this point you might as well sign in at webmail.

Ok, so I read this and thought Mac user. Checked with the forum software and yep it indicates Mac user. You can't actually execute the package downloaded in any other operating system without running an installer. But Apple. They are special. I understand the next version of Thunderbird has had code inserted to block this silly ability of Apple operating systems, but refuse as I do to pay the Apple tax I really have no hands on experience in the past 20 years with their products.

Try installing the DMG instead of running it from the system temp folder where everything gets deleted every restart.

You relationship with Google is not something we can help with really. Personally I do not have two factor authentication enabled on the gmail web site and therefore don't get stupid phone alerts. However I do get alerts every time I "allow" Thunderbird via oauth authentication which can be almost as annoying as they scatter gun them to every registered method of contact, SMS, multiple email addresses etc.