Question about strange filter behavior

[tomdkat]

Hi! On my mom's computer, I have her setup with Thunderbird 68.10 (I think) on Ubuntu 20.04.1 (64-bit). Anyway, she has a Gmail account setup using POP3 and mail comes in perfectly. I setup a few message filters setup to route messages to various folders and the filters work fine.

The issue: today, I watched my mom's new email get downloaded and several messages were routed to the appropriate folder (I saw the folder icon update with the unread message count). After the messages appeared in the designated folder, they disappeared from the folder. I went to the Junk folder and found the messages that should have been in the designated folder in there (junk folder) instead. It seems as if the junk filter ran against sub-folders in addition to the inbox. Is this possible?

Thanks in advance!

Peace...

[tanstaafl]

There are three types of filters - message filters, adaptive junk controls, and trust headers (where you tell Thunderbird to trust the custom headers set for SpamAssassin etc.)

Supposedly the order of processing is:

Message filters
"Trust header"
"Adaptive junk" (junk mail controls)"

But a few years ago they added a list box in message filters that let you choose between filter before or after junk classification. That also means the order can be account specific. Look at your message filters and see if you have "Getting new mail: Filter after junk classification".

http://kb.mozillazine.org/Message_Filters
http://kb.mozillazine.org/Junk_Mail_Controls

[tomdkat]

Thanks for the reply. I checked the message filter setting, for the related filter, and it's set to "Getting new mail: Filter before junk classification".

So, I expect Thunderbird to behave like this:

1) New mail comes into the inbox
2) The filter for 'bob' runs and finds a message that matches the filter criteria
3) Message 'bob' is moved to the "Bob" folder
4) After all new mail is downloaded, check inbox for Junk/Spam
5) Move all Junk/Spam message to the Junk folder
6) The message that was moved to the 'Bob' folder still remains in the "Bob" folder

This is what's actually happening:

1) New mail comes into the inbox
2) The filter for 'bob' runs and finds a message that matches the filter criteria
3) Message 'bob' is moved to the "Bob" folder
4) After all new mail is downloaded, check inbox for Junk/Spam
5) Move all Junk/Spam message to the Junk folder
6) The message that was moved to the "Bob" folder is moved *from* "Bob" and put in the Junk folder

So, I'll try disabling the "Bob" filter and see how things behave. I expect the message to remain in the inbox until the junk filter runs. Then, I'll enable the "Bob" filter and will temporarily disable the junk filter and see what happens.

Thanks again!

Peace...