re :Nothing is set at the email server level to filter for junk

All servers have their own spam filters to detect potential spam. Sometimes you can influence these settings but not always. For example: microsoft servers - you may like to read this:

• https://postmaster.live.com/pm/junkemail.aspx

gmail servers: They also have spam filters but do allow you to create an approved senders list to bypass spam filters.

• https://support.google.com/a/answer/2368132?hl=en

If you are talking about an IMAP account then if server auto puts email into the server Spam folder then Thunderbird has no control over this as it simply displays what is on the server.

If you are talking about a POP mail account, then it cannot download anything which the server puts into the server Spam folder, so this type of account is then relying on Account Setup eg: whether 'Trust junkmail headers....' has been selected and/or adaptive junk controls and/or Message Filters created by you.

Whilst you had the Thunderbird junk controls enabled, data would have been collected as you were in the process of training the Thunderbird Junk filter. Does the log show any activity?

In Menu app icon > Preferences > Privacy & Security 'Junk' section I presume you: unchecked 'when I mark messages as junk' OR did you keep that enabled as you may choose to mark items as junk and want them auto moved when you choose.

unchecked 'Enable adaptive junk filter logging' If this was enabled then it might show something is occuring. The most recent will be at the bottom. Does the 'Show Log' button display any logs showing recent activity? Did you click on 'Reset Training Data' to clear anything which you previously set ?

In the Account Settings > Junk Settings I understand you unchecked 'Enable adaptive junk mail controls for this account' to stop it working. This also auto disables all the address books set up as whitelists.

Please confirm this checkbox is not selected 'Trust junkmail headers set by:...' Otherwise any spam score applied by server spam filters may be causing Thundrebird to register it as junk.

Do you have any 'Message Filters' which you created that could be marking items as Junk?

After making those changes did you restart Thunderbird to ensure the current Thunderbird was using those settings?

After update to 91.7.0 mail from known parties are ending up in my junk folder. Junk filtering was apparently re-enabled. This has been a problem for many users years, just Google it!!

After update to 91.7.0 mail from known parties are ending up in my junk folder. Junk filtering was apparently re-enabled. This has been a problem for many users years, just Google it!!

Please note if your particular problem is about Thunderbird auto enabling a checkbox which you had unchecked, then this is not the same problem as the person who asked the question. The person who asked the original question has good emails going to junk, but they do not have 'adaptive junk controls' enabled so setting as 'not junk' will only put email back in Inbox, it's not going to be remembered because the 'adaptive junk controls is switched off. Nor is it fully understood whether the server is marking items as junk which adds another problem.

Are you stating that for that account in Account Settings > Junk Settings You did not select or you unchecked: 'enable adaptive junk mail controls for this account', so it was not running. This would also disable the option to have your address books set up as whitelists.

Immediately after the update to 91.7.0, that checkbox 'enable adaptive junk mail controls for this account' was now selected. However, it is unknown whether any address books were set up as whitelists.

Please confirm- are you using a POP account?

You would also need to check whether you have other products like CCleaner, WiseCleaner or even some Anti-Virus products cleaning up files, because they can cause havoc with session etc files. Those products should not have any access to Thunderbird profile folders.

I'm also wondering if you have more than one 'prefs.js' file in your 'profile name' folder and whether the creation of new 'prefs.js' file coincided with the update.

Just because good email ends up in Junk, does not mean there is one thing causing the problem. Since Imap came along and improved server filters for spam, it has caused many problems which Thunderbird has no control over.

But you are claiming an update changed a setting and that is a different issue, hence why we have to rule out the possibility that other software on computer may have removed required files that store your preferences. If file is removed, then Thunderbird will auto create a new one, but then it may have default settings.

Google may discuss issues that people have with Junk, but often people do not have the Junk settings set up correctly Or they have not trained the Junk controls Or they are unaware that the server spam filters are causing the problem, but I do not usually come across an update changing a setting when no other 'cleanup' software is involved.

Thanks for the replies.

The problem never was with the server (GoDaddy). I checked and there is no filtering or processing at that level. I use an MS Outlook client on one of my laptops and none of the emails received there were marked as junk or spam. It was only with T-bird on my desktop.

I'm not sure if this is what solved the problem, but it has been resolved following a maintenance update to T-Bird 91.7.0 about a month ago. No more mail marked as junk!