I have Thunderbird 78.12.0 installed on my laptop and desktop. Both run on windows 10. When I move the data from my laptop to my desktop as per your instructions Thunderbird runs 100% on the first startup, but when I close and open Thunderbird up again it open up, but to basically a blank thunderbird screen with no information in it and display only a few menu items also. If I repeat the profile copy process again, then it open 100% but again I have the same problem after closing and starting it. Update: It seems the problem file is prefs.js. I have to replace prefs.js every time before I start thunderbird in order for it to run correctly. Is there any solution to it?