The rev 68.8 Thunderbird upgrade stops being able to read the existing profile, usually within 24 hours. (Windows 10, no custom profile. no custom anything). I get the pop-up box complaining about trying to read an old profile. I can re-install Thunderbird, and then it works fine. And within another 24 hours, it stops working again. Any thoughts or suggestions are welcome. My next step is to completely remove Thunderbird (and all profiles), reboot, and reinstall from scratch. Um, have to back up local folders. Painful.