Further to my earlier post I have found a possible workaround, based on other advice elsewhere.

In Bitdefender -> Protection -> Online Threat Prevention -> Encrypted web scan. Toggling this setting to off seems to stop the corruption occurring.

The downside of this is of course that protection is potentially reduced, so make your own decisions.

It does appear to point the finger at Bitdefender.

Further to my earlier post I have found a possible workaround, based on other advice elsewhere. In Bitdefender -> Protection -> Online Threat Prevention -> Encrypted web scan. Toggling this setting to off seems to stop the corruption occurring. The downside of this is of course that protection is potentially reduced, so make your own decisions. It does appear to point the finger at Bitdefender.

That seems to have worked for me. However I still wonder why, after using Bitdefender forever, this has just started happening. Maybe this needs to be brought to their attention?

Maybe this needs to be brought to their attention?"

I opened a discussion in Bitdefender Forum. It would be usefull to add this workaround.

Just tried the work around from psil, turned off Bitdefender Total security/encrypted web scan... bingo email is properly displayed. I guess I have to contact Bitdefender Support.... or will the problem be fixed by Thunderbird?

Thx to all!

To everyone, I have confirmation that the Bitdefender develpment teams are actively looking into this.

https://community.bitdefender.com/fr/discussion/104823/mails-in-thunderbird-showing-as-source-code-with-bitdefender-installed#latest

psil wrote : > In Bitdefender -> Protection -> Online Threat Prevention -> Encrypted web scan. Toggling this setting to off seems to stop the corruption occurring.

This solution worked for me.

Many thanks to psil!

As suggested above, I had previously installed/uninstalled BitDefender (which asked me to close Thunderbird... hmmm). After reinstalling, the first test post was successful, but then the problem returned.

I'm getting this same issue

I have disabled Bitdefender entirely, but the issue remains the same I have test Thunderbird to troubleshoot mode with everything reset and add-ons turned off. The issue remains the same

Just to cover bases, I have also done what others have suggested and in Bitdefender, went to: In Bitdefender -> Protection -> Online Threat Prevention -> toggle off the setting Encrypted web scan I also set the local e-mail protection to"Do not Scan e-mails".

Nothing is working. I am awaiting important e-mails and cannot read anything that's coming in.

On the server and on my phone, they are readable.

Thunderbird is now completely useless to me.

I'm getting this same issue I have disabled Bitdefender entirely, but the issue remains the same I have test Thunderbird to troubleshoot mode with everything reset and add-ons turned off. The issue remains the same Just to cover bases, I have also done what others have suggested and in Bitdefender, went to: In Bitdefender -> Protection -> Online Threat Prevention -> toggle off the setting Encrypted web scan I also set the local e-mail protection to"Do not Scan e-mails". Nothing is working.

In that case you should post your own question so as not to complicate this question which is marked solved for the original reporter. And do the following...

• Start Windows in safe mode with networking enabled - https://support.microsoft.com/en-us/help/12376/windows-10-start-your-pc-in-safe-mode
• Still In Windows safe mode, start Thunderbird in Troubleshoot Mode - https://support.mozilla.org/en-US/kb/troubleshoot-mode-thunderbird

Are new messages now better?

That seems to have worked for me. However I still wonder why, after using Bitdefender forever, this has just started happening. Maybe this needs to be brought to their attention?

Yes, please do so.

The BitDefender workaround worked for me. I've reported this situation to both Bell and BitDefender.

For a more permanent solution, I wonder if it's possible to move my Sympatico mail accounts from POP to IMAP (which doesn't seem to be affected by all this). On the Bell Mail site, they seem to give the option of using either one as a server setting (see screenshot). I'm just not sure it would work so I guess it's off to Bell to figure that out!

I just now found this question. Yesterday I posted with the same issue. The name of my posted question was "Messages are suddenly not showing subject or from, and body looks like "View message source."

The below works perfectly!!! Thank you for whoever it was that found the solution originally:

In Bitdefender -> Protection -> Online Threat Prevention -> Encrypted web scan. Toggling this setting to off seems to stop the corruption occurring.

The downside of this is of course that protection is potentially reduced, so make your own decisions.

It does appear to point the finger at Bitdefender.

It is Bitdefender!! I have had exactly the same problem from 11th August - just with two BT POP accounts - Gmail IMAP is fine. Sending from POP to IMAP is fine - IMAP to POP corrupted. Windows 11 +Bitdefender Internet Security +Thunderbird 128.13.0esr (have not updated for a while!!).

Removed Bitdefender completely (incl. Registry entry) and activated Windows Security - all OK (sigh of relief!!). Re- installed Bitdefender and problem back again. Progressively disabled Bitdefender email protection, antispam, vulnerability, advanced threat - all no change. Disabled all on-line threat and OK. Re-enabled email (incoming) antispam, vulnerability, advanced threat - still OK. Re-enabled all on-line threat - problem back again. Progressively disabled Online threat option - with Encrypted web scan off - OK. All Online threat options on except encrypted - still OK. Encrypted back on - problem back again - Encrypted off - OK!!

Has anyone got a response from Bitdefemder.... I did not so far.... Is the problem fixed? I am still using the work around but it is annoying.... Thanks to all of u

Has anyone got a response from Bitdefemder.... I did not so far.... Is the problem fixed? I am still using the work around but it is annoying.... Thanks to all of u

I saw a post from Alexandru on one of the Bitdefender forums. Bitdefender is rolling out an update, which is a temporary fix until they issue a permanent one.

https://community.bitdefender.com/en/discussion/comment/356182?tab=all#Comment_356182

Right-click on the Bitdefender icon in the Notification Area, select Update Now and run the update if available, then reboot.

It solved the problem for me. New messages are now coming through fine, although the messages that came in before the update are still messed up.

I got a note this morning (Aug 14) acknowledging the problem was caused by a fix they distributed on Aug 11. They said they had reverted the problem fix and to do a manual BitDefender update to install it. I did that and toggled the Encrypted Web Scan back on, and Thunderbird downloads now work properly again. Doing the manual update is very simple. Right-click the BitDefender token in the task bar and select Update Now.

I got a note this morning (Aug 14) acknowledging the problem was caused by a fix they distributed on Aug 11. They said they had reverted the problem fix and to do a manual BitDefender update to install it. I did that and toggled the Encrypted Web Scan back on, and Thunderbird downloads now work properly again. Doing the manual update is very simple. Right-click the BitDefender token in the task bar and select Update Now.

That's brilliant, barry54, thanks for posting that here. Really pleased the BitDefender team managed to make the fix so quickly. They've earned my long-term business!

Thx! :-)

If anyone's problem is not resolved, please make a NEW question with https://support.mozilla.org/en-US/questions/new/thunderbird