Hello there amylaw. We have read your message. We try to help you.

Try to start up in safe modus Thunderbird. Configure what can cause the issue by deleting security software or ad blocking software. https://support.mozilla.org/en-US/kb/troubleshoot-mode-thunderbird

If some emails won t close properly. https://support.mozilla.org/gl/questions/1362428

Thunderbird won t close correct.

To force quit, press Option+Cmd+Esc, then select what you want to force quit. To make Tbird quit completely, you need to use Thunderbird > Quit Thunderbird from the menu. The other way is to right-click the icon in the dock and choose Quit.

Your Thunderbird is continues crashing.

https://support.mozilla.org/en-US/kb/thunderbird-crashes

Did this solve something?

Greetings Firefox volunteer.

One of my problems is that I can't see any add-ons in the addon tab. That means that I have none added onto Thunderbird, therefore no add-ons can be interfering with my Thunderbird.

Yes, I can shut Thunderbird down using Task Manager, but this isn't how Thunderbird was designed to work, which indicates a problem. Besides, it's a clunky way of exiting when I am closing down my machine.

Here is the latest Crash Report from 2 days ago: bp-3f072008-5973-4e60-ab08-c43df0220614 It shows that 2 threads have failed. I have no idea what that means.

Any help would be appreciated.

Hello there again.

I t sounds that you are using a non using method. No add ons no security? The software does not close good. Oké but is there software that helps your computer / laptop?

Taskmanager is more for closing software that really not oke. That is grabbed of the internet- sites. Installed and oké but suddenly it s not working how has to do.

But for Thunderbird it s possible to react like that. Where did you grabbed this software? Oké.

There is a method to solve this issue. Close Thunderbird and clean your pc or laptop from From all of the software of Thunderbird.

Clean your pc with a good cleaner like ccleaner to download on the internet.

Take a clean fresh Thunderbird version from us. Install all the software and open your Thunderbird software again. It could that the issue is solved.

After that try to search for some security software. Or ad blocker malware software.

https://www.thunderbird.net/en-US/thunderbird/all/

https://addons.thunderbird.net/nl/thunderbird/

Greetings Firefox volunteer.

I did everything you suggested (again): Deleted Thunderbird, including folders in Users, Programs, and Programs86 Emptied trash Cleaned with CCleaner Turned off all browser security (Norton, MalwareBytes) Got new download from Thunderbird, not 3rd party Did clean install, which generated New profile.

Still cannot access Thunderbird addons (through add-on tab) Still will not close completely on exit.

For what it's worth, this is a new Windows 11 machine. The only other problem with it is that it will not install Windows Update for Windows Security platform - KB5007651 (Version 1.0.2109.27002) -- Install error 0x80070643.

Hello there again.

System settings are not filled in correct at the configuration options. It could besides that a malware infection. The missing of some drivers. The laptop with windows 11 is a new pc. It has to be all there if it’s a new machine.

The option could be that there are missing files? The other option of this issue is that older version of Os aren t removed correctly. And installed the new Os or system software above that.

The option to erase your current Os is there. The Win update to update it again? And first clean your pc with a cleaning tool.

Installation error. After a clean and good reinstall of your Win version. Then install Thunderbird Software again.

Firefox volunteer.

Hello there again.

You can try to roll back to win version 10. Look if it s all there.

Clean the pc from all win 11 stuff and files and update again to win 11. Make some backups from your stuff on usb.c.

Roll back to Win 10. Start menu > Settings > Windows Update > Advanced options > Recovery > Previous version of Windows.

It also could be a minor thing like a spam or infection. It s your choice to choose the better option and that is for the reinstall options. But that takes time to do.

https://support.mozilla.org/en-US/kb/thunderbird-software-update-failed

Greetings Firefox volunteer.

After I read your suggestions above, I did some research on recovering Windows 11. It turns out that Windows 10 and 11 really need a good install to work properly. If not it causes all sorts of problems. So that fits. I worked my way towards more and more drastic recovery solutions. But in the end, I had to completely delete my personal data and reinstall Windows 11 -- what we used to call "formatting the hard drive". But it seems to have worked. Thank you for your help.