Avast and Mozilla Thunderbird certificate problem

Avast Free Antivirus / Premium Security
1

After installing Avast Internet Security, email client Thunderbird always says that mail server certificate is invalid. I have looked for this issue and learned that I must import Avast certificate to the Thunderbird. There are some images about that but they belong to the older version of the Avast. And unfortunately, I could not find where I can export Avast email certificate on the latest version of Avast. Could you please help me with this issue?

Thank you

2
  1. Download Avast Internet Security: https://files.avast.com/iavs9x/avast_internet_security_setup_offline.exe
  2. Follow instructions: https://www.avast.com/uninstall-utility (Run this tool for all prior installed Avast versions…!!)
  3. Reinstall Avast with the downloaded installer from point 1.
  4. Reboot.
3

Will this solve the problem?

4

Most probably, yes.

5

I asked you because my Avast was a fresh install on a new Windows

6
  • Which version of AIS…?
  • OS…? (32/64 Bit…? - which SP/Build…?)
  • Other security related software installed…?
  • Which AV(s) did you use before Avast…?
7

Version : 19.1.2360 (build 19.1.4142.0)
OS : Windows 10 Build: 18290
No other security software installed
I installed fresh windows 10 and then fresh Avast with above version. No other antivirus installed before and using now

8

OK, follow the instructions from Reply #1 to the point and report back.

9

Online (recommanded) or offline (Asyn #1 link) version ?

When Asyn says “Most probably, yes.” it is not only about the fresh installation but also about installing with an “offline” version.Did you like this ?

Sorry if you understood correctly before and the procedure was followed to the letter.

10

I did as you say. Uninstalled with uninstall.exe and then installed offline but unfortunately, it did not help. I need the avast mail shield certificate.

11

Install a stable build of W10 and try again.

12

Why are you talking about OS windows. The conflict is between Thunderbird and Avast. I think it is not about Windows… We should focus on right point to solve the problem

13

Well, 18290 is no stable release of W10 and therefore not supported.

14

Well, maybe I didn’t read your first message correctly.

Do you talk about this FAQ
https://support.avast.com/en-ww/article/Troubleshoot-invalid-email-certificate
if so, I understand why you didn’t find it, avast often tends to complicate things :-[
You can find the export of certificates in the new IU:
General->Troubleshooting->old settings … then follow the FAQ above

very intuitive , isn’t it :cry: :wink: ;D

15

hey, i just had the same problem. with the new ui.

chris… had the right solution, i was at troubleshooting already by myself but he found the right option.

thank you

16

Thanks, Chris. Your suggestion solved the problem. You are the one solves the problem, and Asyn you are bighead useless guy just saying “NOT SUPPORTED”. Chris helped me and the problem solved.

17

Well, it is as I said, Avast officially doesn’t support insider prewievs. If it works for you, good - else, bad luck.

18

Hi, folks

I would add some extra content for this thread maybe it will useful for somebody later becuse I had to solve similar/same issue.

So after the user installed the latest version of Thunderbird (at this time 78.4.xxx) all sending and receiving activity just stopped and TB throwed message windows with “can’t validate the certificate” blabla.

First I tried to jiggling with security.tls.version.min , security.tls.version.enable-deprecated TB settings but it did not help.

After that I found a post about the Avast / Mail shield certificate magic (https://support.avast.com/en-ww/article/91/ , https://support.avast.com/en-ww/article/Troubleshoot-invalid-email-certificate). So I saved that certificate and tried to add to TB but it replied that this certificate has already added.

I deleted the related certificates and tried to add the Mail shield certificate again, it didn’t solve the problem. (Of course I’ve restarted TB several times between of these events)

After that I just added this certificate to Win10 “Local computer” certificate storage, and that was the solution.

TB started working but the very first time it asked confirmation of the certificate(s).

I don’t know is this a really hacky or stupidly dangerous way to solve this problem, but at least I didn’t have to reinstall TB, AVAST or the whole machine.