Please post your crash IDs here https://support.mozilla.org/en-US/kb/mozilla-crash-reporter-tb#w_viewing-crash-reports

ID: d069a141-4d96-4981-98d1-630f00191211

I'm not sure what to do. The problem is still not fixed! please give the the details instruction.

The crash report, and the Bugzilla reference, point to Bitdefender. I would start by disabling the option to scan incoming and outgoing email:

https://www.bitdefender.com/consumer/support/answer/2092/

If you're not attached to Bitdefender, remove it and use Windows Defender, with the TB profile folder added as an Exclusion in WD settings.

Awesome! I deactivated the anti spam option, added thunderbird.exe as an excepted application in Bitdefender and TB works.

Thank you sfhomes very much. You save my time for install then reinstall TB. Other thing, since trying to solve the problem "my way" I played with the TB profile files and I lost all my old folders and messages. Is there a way to recover those?

Regards, David

Is your account IMAP, and if so are the messages still visible on the webmail portal? Do you have any kind of backup?

Yes my current account is IMAP. I'm not sure if the previous TB profile is in POP3 or IMAP. Also, the lost folders I created in the TB not in the optus webmail! I can't find any lost folders, messages on my optus webmail!!!

Help/Troubleshooting Information, click about:profiles. Are there any other profiles besides the one currently in use? If there are, your lost folders may be still be available.

I was going through the same thing. I had been running fine till the update 12/20/19. After the update I got a crash report. One of the recommendations was to install over the current install. I installed 68.3.0 again. It recognized there was already an install. I launched gave message about older version create new profile. It wouldn't continue without this so I did. Then it crashed. I then found this post. I have bitdefender as well and it appears to be the problem. I have put an exception in place and TB launches but there is nothing there. In profile manager there are 2 profiles. Default and Default-release. Default-release appears to be the new profile and if I choose default it gives me the profile error message, a new version of TB has changed your profile etc. I allowed the new profile to update as the download is not the latest version or update. NOTE!: update was just churning till I turned off bitdefender protection, then it completed. May have been just coincidence. After the update I could use Default which had all my emails etc in it.

to allow the original default profile to be used, start thunderbird from command line as

thunderbird.exe -P --allow-downgrade

Did you have good results ??

Thanks for your asking Wayne. I have given up searching for the old profiles. I have to be more careful next time to backup the profiles regularly. The lost folders and messages are not so important, they are just a memorial conversations with friends that I'd like to treasure. Thanks again, Wayne and everyone in this forum.

If you still crash with Bitdefender enabled, please create a new topic https://support.mozilla.org/en-US/questions/new/thunderbird/form and put Bitdefender in the title. Thanks