I really need help. If you have any idea about what I coud try to do, please tell me!

The report indicates the antivirus is Avira, so I suggest you remove it at least temporarily, as there's a good chance it's causing the crash. As for the apparently empty profile, see if the account information is present in prefs.js, and if not, see if there's an older version, e.g. prefs-1.js, that can replace it.

https://support.mozilla.org/en-US/questions/1324156

Hi sfhowes, thanks for your answer. Alas, I do see all my mail in the folder, but there's only one prefs.js file, which is almost empty, no older version there. Aparently is was rewritten in the crash.

I do have a backup that's 2 years old. I was hoping I could install that, and copy the new mail into the old profile. But if I do, Thunderbird recognises the old mail but not the new. I tried to delete global-messages-db.sqlite but that didn't bring anything new.

In a new attempt I migrated the 2 year old profile to a new install, then I copied all files from my profile-after-the-crash to it, then I deleted global-messages-db.sqlite and replaced the new prefs.js with the 2 year old prefs.js.

This sort of works partly. The folder structure in Thunderbird looks weird. But I can see the mails from mail adresses that I already had 2 years ago. Including mails form last week. But all mail from mail adresses that were added later, are still invisible.

Is there a way to write prefs.js myself? (while I'm asking I'm thinking: that will be too complicated...)

It's too bad there's no prefs-1, prefs-2, or ... prefs-N. If the accounts and settings are the same from 2 years ago, you might be able to copy prefs.js from the backup. But it's probably better to just create a new profile from Help/Troubleshooting, about:profiles, add the accounts, and transfer the local mail from the old to the new profile. This post explains how for the mail and address books. IMAP accounts will download mail from the server on the first sync.

Thank you again. I have both pop mail and IMAP. Most accounts didn't exist two years back. So if I understand you rightly, I should: 0: export address books from the old profile that's still running now 1. uninstall and install Thunderbird, 2. create a new profile 3. add the mail accounts 4. close Thunderbird 5. copy all files from the just-after-the-crash profile to the new profile except prefs.js 6. delete global-messages-db.sqlite 7. start Thunderbird again 8. import the address books.

Is this correct?

No need, or benefit, to reinstalling the program, as all user data is in the separate profile folder. Just add your accounts to the new profile and copy the mbox files from the old profile to Mail/Local Folders in the new profile, to avoid mixing newly set up accounts with old mail. A new global database will be created automatically in the new profile.

OK, 8 days of work, and Thunderbird regulary refusing to add an account (pushing the button 'add e-mail account' simply had no effect, no window opening), but I managed to get almost all my mail and accounts back, sadly losing all addresses of the past year as my abook.sqlite and history.sqlite were empty after the crash.

Thanks a lot for your help sfhowes. What a week....