Can you post any crash report URLs? They are under Help/Troubleshooting Information.

This looks like a security/AV app incompatibility. Run Windows in safe mode and see if TB works properly.

fraethir, your crash report IDs please?

Apologies. Hard to see my email notifications when my phone is the only thing reliably getting email.

bp-a56e6067-e0d4-4752-9471-c57b70191216 should be one. bp-0dfc526f-8c29-4b76-b95b-f7e730191216 should be another.

I had the hope it was transient AV behavior, but. I'm seeing no indication that the app is being blocked, and it DOES run when you use the installer (then allow it to run the app when the installer is done).

Fresh one from today is: bp-4b45adc1-e2f1-4ffa-9a20-50a380191225

sfhowes said

Can you post any crash report URLs? They are under Help/Troubleshooting Information. This looks like a security/AV app incompatibility. Run Windows in safe mode and see if TB works properly.

Took your advice, noted that it ran with administrator permissions, and went back through AV with a fine-tooth.

No logged errors, no logged alerts.

AV in use: Bitdefender (Bitdefender Total Security 2020, Build 24.0.14.80) Problematic feature/service: "Advanced Threat Defense"

When this is turned on, Thunderbird crashes on load (without the AV even mentioning it in any log I could find). If you turn the feature off, or give it a specific exclusion for Thunderbird.exe, it loads. Moving my 'real' profile back into place to see if it continues to load, but good call.

Mozilla, if you're listening, I'll tell Bitdefender they're being dumb. But you should too, please.

Thanks again!

The atcuf32.dll crash was recently reported by another Bitdefender user:

https://support.mozilla.org/en-US/questions/1274953

Excluding the TB profile folder from AV scanning and disabling the scanning of secure (SSL) connections is a general recommendation for any AV app.

http://kb.mozillazine.org/Antivirus_software

The "ATD" module watches for running applications to exhibit 'exploits', apparently. The controls to exclude thunderbird are entirely separate from scanning behavior (note that scans, on-demand or otherwise, don't mess with the application. On the "Advanced Threat Defense" module (with its seperate exception list). In this case at least.

Hi fraethir.

https://forum.bitdefender.com/index.php?/topic/81641-latest-update-breaks-thunderbird/&do=findComment&comment=293676 describes a process to submit information to the vendor, information then need to diagnose the problem.

If you can give them that information it would be very helpful.

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

We are looking for updated information.

When using newer versions, do you see a problem if you enable the features of Bitdefender which caused your problems? Please create a new topic https://support.mozilla.org/en-US/questions/new/thunderbird/form and put Bitdefender in the title. Thanks