Only your first crash ID is listed above.

But it points to Bug 1458562 - Crash in UserCallWinProcCheckWow after win10 1803 update with 3rd party smartcard software

I forgot that bug is secured.

See https://bugzilla.mozilla.org/show_bug.cgi?id=1463153 and https://bugzilla.mozilla.org/show_bug.cgi?id=1480795

I dont have a smartcardreader as far as i know.. (however there is an sd/mmc/tflash/xc card reader built in to my system, is ths the same?) I closed all possibly conflicting software like onedrive and dropbox It does not help when i stop running the third party apps and/or run thunderbird in safe mode. Crashing only occurs if i attach a file to a new mail, takes about 10 secs, so i type the mail first and do the attachments afterwards and swiftly click on send.. thunderbird still crashes, but most time the mail has been sended. (poses problems cause i use it to send my invoices, and i need to be sure these are really send) It does not matter if i use another mail-account in thiunderbird, same thing happens.

p.s. thans for the very swift reply!!

> Crashing only occurs if i attach a file to a new mail, takes about 10 secs

What are your other crash IDs?

> I dont have a smartcardreader as far as i know..

The module list, which shows non-Thunderbird and non-Microsoft code, sometimes has clues.

Perhaps pwmCapBtn.dll - related to Lamantine Software Sticky password?

Besides Sticky Password, it appears you're using ESET Security. Is it scanning outgoing mail?

I did a search on the pwmCapBtn.dll and found this dll was used by ESET password manager. I disabled this cause i don't even use it, and this seems to have solved the problem! Have had an email with attachment waiting for severeal hours, and thunderbird didn't crash. Great! Thank you so much!