Hello there We have read the message. We try to help you.

it appears that you have already read and used all these safe mode instructions.

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

If you work a lot with the computer, you can also create a debit number on your hard drive, which will sometimes have to be set to 25% free space.(Win 11 .)

You can also take a look at the .msf files in your system for thunderbird.

Sometimes these appear to be damaged during use or subsequent updates. Try deleting them. and restart these will be created again after this. ​

Greetings firefox volunteer

Hi, thanks for your answer. I confirm that I tried the "troubleshoot mode", disabling everything and (now) even removing the .msf files. The last option just aggravated the situation as during the download of the emails Thunderbird freezes even sooner that it uses to do. I'm starting to think that the download interacts with some Windows 11 component, but I think I already tried to toggle everything.

After two days of "trying to fetch all the emails after the .msf deletion", I decided to purge my installation and start from scratch, reinstalling the latest supernova version (as the previous installation got upgraded). I'll wait a few days before marking this as solved/closed because every time I try to reinstall Thunderbird, it only gives me 2-3 days of snappy loading times before returning to the freezes.

https://wiki.mozilla.org/Thunderbird:Testing:Memory_Usage_Problems has a fairly comprehensive list of items to check

Thanks Wayne for the list, I never saw it before, and it may come handy in the future. However, I'm not having any issue so I guess it actually was a corrupted configuration due to a version upgrade.

Thanks to both for your answers!