Avast WEBforum

Consumer Products => Avast Free Antivirus / Premium Security (legacy Pro Antivirus, Internet Security, Premier) => Topic started by: avastmobile2 on January 29, 2021, 01:25:12 PM

Title: Thunderbird keeps saying there's a problem with a certificate
Post by: avastmobile2 on January 29, 2021, 01:25:12 PM

I've been using Thunderbird and Avast (Free) for ages without any problems whatsoever. But since last month, every time I start Thunderbird for the first time after booting Windows 10, this popup appears:

(http://www.whutever.com/privateimages/thunderbird.png)

I need to "Confirm Security Exception" before I can receive emails. At first I thought this was a problem with Thunderbird but now I know it's actually Avast who is causing the problems.

If I understand correctly, in order to be able to scan incoming emails, Avast puts itself between the internet and your email client. For secure connections, it creates a certificate which it presents to the email client. I don't know if this certificate is a self signed certificate that is created on the spot or if it's a certificate that is retrieved from Avast. My knowledge about certificates is limited.

Anyway, what apparently happens, is that this certificate changes each time my machine is rebooted.

Does anyone know how to fix this?

Title: Re: Thunderbird keeps saying there's a problem with a certificate
Post by: Asyn on January 29, 2021, 01:28:01 PM

-> https://support.avast.com/en-ww/article/Troubleshoot-invalid-email-certificate

Title: Re: Thunderbird keeps saying there's a problem with a certificate
Post by: avastmobile2 on January 30, 2021, 10:46:57 AM

Thank you for your answer. Unfortunately that was something I had tried earlier already and it did not solve the problem. I just tried it again (in case I did something wrong the previous time) and Thunderbird tells me "This certificate is already installed as a certificate authority".

Title: Re: Thunderbird keeps saying there's a problem with a certificate
Post by: Asyn on January 30, 2021, 11:00:42 AM

- Which version/build of Avast Free..?
- OS..? (32/64 Bit..? - which SP/Build..?)
- Other security related software installed..?
- Which version/build of Thunderbird..?

Title: Re: Thunderbird keeps saying there's a problem with a certificate
Post by: avastmobile2 on February 03, 2021, 08:12:49 AM

- Windows 10 Pro 64-bit 10.0.18363
- Avast Free 20.10.2442 (version 20.10.5824.626)
- Thunderbird 78.7.0 (32-bit)

Title: Re: Thunderbird keeps saying there's a problem with a certificate
Post by: Asyn on February 03, 2021, 08:30:14 AM

1. Download Avast Free Antivirus: https://files.avast.com/iavs9x/avast_free_antivirus_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.

Title: Re: Thunderbird keeps saying there's a problem with a certificate
Post by: avastmobile2 on February 04, 2021, 02:32:39 PM

Followed your instructions. Also did this again:

https://support.avast.com/en-ww/article/Troubleshoot-invalid-email-certificate

Problem remains. It seems Avast creates a new certificate every time the computer is restarted.

Title: Re: Thunderbird keeps saying there's a problem with a certificate
Post by: Asyn on February 04, 2021, 02:51:13 PM

Strange, let's dig deeper...

1. Enable debug logging (Menu > Settings > General > Troubleshooting > Enable debug logging) and reproduce the issue.
2. Follow instructions: https://support.avast.com/article/33/ and post the File-ID or name of the Support-File here afterwards.