Two days ago, Thunderbird suddenly did not start anymore. I tried safe mode, set the profile ini to ask at startup - nothing helped. What striked me as odd is that I cannot stop the thunderbird.exe at all - tried Task Manager, then Process Explorer, also Process Hacker. Always had to restart the machine to try something new. Copied the whole profile to an old machine and it worked there. Cleaned it up there (remove add-ons), copied it back - opened blank (no emails) in safe mode, but not at all in regular mode. Noticed that on the initial machine it was version 68, on the old version 60. So uninstalled the 68 and installed 60 after removing data from profile folder. No luck after restart. Still cannot stop thunderbird.exe. Not sure what else to try. Wondering if it might have to do with updating my Kaspersky Internet Security. But even after disabling that no success.

Thanks