I disabled Automatically mark messages as read but it isn't working

Does that also happen in Troubleshoot mode?

Yes, it happens in troubleshoot mode too.

Marks them read where? In Thunderbird, or on the server?

In Thunderbird on my Windows 11 PC

I will try again, Check in your webmail before you open Thunderbird. Are the message marked as read

I can see the messages come in as Unread and then immediately change to Read

Do you use the Bitdefender toolbar in Thunderbird?

Yes, I'm using the BitDefender tool bar

Bitdefender toolbar is known to cause your issue. Try to uninstall it https://support.mozilla.org/fr/questions/1447447

I successfully removed the Bitdefender toolbar but the problem is still the same: all emails automatically get marked as read

does anyone else have a solution?

Which Thunderbird theme do you use (Add-ons Manager > Themes . .) ? I remember a long discussion in the German Thunderbird forum about the same problem in version 140.0.1 last year https://www.thunderbird-mail.de/forum/thread/97088-nach-update-ungelesene-email-nicht-mehr-fett/?pageNo=1 We didn't find the cause of the issue and when I saw the user's screen shots there was a bright difference between read und unread message display. The discussion ended with a workaround: https://www.thunderbird-mail.de/forum/thread/97088-nach-update-ungelesene-email-nicht-mehr-fett/?pageNo=4# by using the following CSS code to modify the font in the thread pane

/* thread pane font */
#threadTree tr[is="thread-row"] {

font-family: Palatino !important; }

There also is a second code which can be tested in combination with the upper code

/* thread pane unread colour table view */
#threadTree tr[data-properties~="unread"] {

color: blue !important; font-weight: bold !important; }

If no cause and no solution can be found for your problem you could test the CSS codes: • go to Settings > General >>> sroll to the bottom an click Config Editor.... Search for the preference toolkit.legacyUserProfileCustomizations.stylesheets and toggle its value to true • Open a text editor such as Notepad, copy-paste the above codes in the text editor window and save the file as userChrome.css (attention: remove the .txt suffix your system will add to the file name) • On your desktop create a new folder, name it chrome and move the userChrome.css file in the chrome folder • in TB go to Help > Troubleshooting Information > Profile Folder > Open Folder, then quit TB • move the chrome folder directly in the profile folder, close the profile folder and restart TB Any visual difference now between unread and read messages ?

Within the last 6 weeks I migrated to Win11. I migrated my apps that would work and Thunderbird also. Got a recent update of TB. Finally MOSTLY disabled the bloody thread thing in TB.

But ever since running on Win 11, I cannot stop TB from marking my messages as read even if I have never opened them. Even If I never use another device to connect with email. I try thigns and it works for like a day and then poof. ANy email that comes in is read as per TB.

It is killing me. I run my biz on email and if it is unread I give it low priority. But turns out it is marked read without any action from me.

Really! I do no want to migrate to another email program.

help!

Within the last 6 weeks I migrated to Win11. I migrated my apps that would work and Thunderbird also.

Migrated Thunderbird how exactly. an install and a new setup is not a migration

. Got a recent update of TB.

You get support with the release version and ESR versions of the product. Not "a recent release."

Finally MOSTLY disabled the bloody thread thing in TB.

That says you migrated nothing you did a full new install of Thunderbird and set it up again from scratch.. Otherwise you would not know that you had changed operating systems when in Thunderbird nothing would have changed.

But ever since running on Win 11, I cannot stop TB from marking my messages as read even if I have never opened them. Even If I never use another device to connect with email. I try thigns and it works for like a ay and then poof. ANy email that comes in is read as per TB.

Perhaps consider disabling the known problem which is bit defender. YOu can not fix ac defective bitdefender by changing something in Thunderbird.

It is killing me. I run my biz on email and if it is unread I give it low priority. But turns out it is marked read without any action from me. Really! I do no want to migrate to another email program. help!

Then get rid of bitdefender. It is simple enough to just run with Windows defender, I have been doing it now for years on Windows 11.