In order to get things working again, I had to do a reinstall/repair of Windows from an ISO file.  An hour later, I am up and running.  I inadvertently tried to install Thunderbird (not Beta), and it would not open.  So I moved all my AppData (local and roaming) files to other locations.  I deleted the Thunderbird folder in the AppData>Local directory, and renamed the Thunderbird folder in AppData>Roaming to XThunderbird.  Then I downloaded the current Beta install file and ran the installation. 

I woke up this morning to discover that a Windows 11 update completely goofed up my laptop. When I tried to open Thunderbird Beta, it acted like I had never set up the program and would not load my profile. So I saved my profile to several locations and then uninstalled the program. But there were numerous other problems that began surfacing. In order to get things working again, I had to do a reinstall/repair of Windows from an ISO file. An hour later, I am up and running. I inadvertently tried to install Thunderbird (not Beta), and it would not open. So I moved all my AppData (local and roaming) files to other locations. I deleted the Thunderbird folder in the AppData>Local directory, and renamed the Thunderbird folder in AppData>Roaming to XThunderbird. Then I downloaded the current Beta install file and ran the installation. Amazingly, upon opening Thunderbird Beta, all my emails and accounts were displayed and up to date (Big sigh of relief!). But when I open the AppData folders there are NO THUNDERBIRD folders in either Local or Roaming. So where has Thunderbird placed my profile? And, just as confusing, where did it find my profile in order to load everything? After maybe 15-20 years of using Thunderbird, I am stumped by this turn of events. But I need to know where my profile is so I can keep it backed up properly.