Avast Mail Shield vs Thunderbird 78.12.0

[Sbordoni]

It's a couple of days that I am tracking down a strange issue between Thunderbird updated to 78.12.0 and Avast Mail Shield (Premium Sec. v21.5.6354.680).

Essentially a cannot connect the POP3 and SMTP servers of my Outlook.com & Gmail.

I verified the accounts' settings by installing Thunderbird into a Windows Sandbox they working fine.

I set TB 'security.tls...' settings, cleanup, and reimport Avast certificate,... but the only thing that worked is to disable both incoming & outcoming mail scan.


Any ideas?

[Asyn]

Hi, best you contact support: https://support.avast.com/contact

[Sbordoni]

Done and before their response, it seems I found the solution:

Dear Support


I already tried to Repair the installation but it didn't work (round 1).

Then I choose to uninstall e re-install again, but installation hung at the very end of the process (round 2).

Then I repeated the process by using Avast Clean utility (round 3), but nothing changed.

Then (round 4):

• I removed it again (always using Avast Clean)
• I waited that Windows Security updated itself,
• I disabled 'Core Isolation',
• and then I installed it again

 but I had the very same problem.

I instantly unblocked the installation process, when I manually switched off the built-in Window Security.


From this point, the program seems to run smooth and fine, and my TB problems disappear.

Then I re-enable Core-Isolation, but I don't notice any problem so far.

I will keep monitoring the situation for 2-3 days.