Burke, here is the deal on the Windows permissions I mentioned.

I'm having some problems with Mozilla Thunderbird since December Windows Updates. I wrote to that forum. The person who answered in Thunderbird forum was a moderator and he said, "Clearly the inability of Win 10 to copy the appdata folder is not something caused by Thunderbird. It sounds more like an issue with Windows permissions, which would also cause problems with Smileycons which is not part of or controlled by Thunderbird."

After Windows Updates ...
1. Gmail no longer appeared in my T-Bird account.
2. I have a program called Smileycons that I have used for years. I can no longer attach the icons to my emails. When I grab an icon and try to slide it onto the email page I get a circle with a slash through it and it will not transfer.
3. I always back up my T-Bird account by going to %appdata%, right click on Thunderbird folder, send to Compressed (zipped) Folder. I tried attempted to do a backup today and right at the very end I got a error Window.
Compressed (zipped) Folders error:
File not found or no read permission.

I've had a lot of various problems since that last update. I had a computer that I was having no problems with, and ended up with lots of problems.