when a filter takes action on an email it is logged. It is not a log of every time each filter is executed, only when they do something.

Make sure you also mark the message as junk in the filter before moving the mail. Thunderbird can not learn unless junk mail is marked as such.

Thanks Matt for your answer. You are right, I have inappropriately used the word "execution". I meant execution with an associated action.

Each time a filter has generated an action (e.g. the filter X condition applies to the message Y and the filter X places the message Y in the trash) there should be a trace of this in the filter log file. Right ?

Actually 90% of the mails I receive go straight to trash thanks to the filters. And again, just right now, 19 messages went through this filtering process which works very well. But the filter log file (verified activated) contains only the 1 trace of the filter action that applied (as explained above) when I created a new filter and manually executed it at creation time for a new spam received.

I noticed this while building a tool on Excel to do some stats on the message filters to identify the obsolete ones and do some clean up as I have accumulated too many filters (454) for several years now to block the spams.

I can try to reduce the number of filters to see if this changes something. I don't understand. Also because under some rare circumstances, they can suddenly all appear. I have not identified these circumstances and at the present time the log is just 1 trace long when it should have about 30 looking at my trash folder.

Best Regards JP

P.S. On my filters I only defined 1 action which is to move the message to the trash folder. This action is ticked on to be performed on manual execution and while receiving mails.

I can define a 2nd action to assign to the message the "Junk" status, however, not doing this should not prevent the 1st action to be logged in the filter log file, I guess.

Your issue is you are chasing your tail. Filters will never be a good way to manage spam. Thunderbirds Bayesian filter is. Over the last 10 years it has got to the point on my machine that is it probably 99% accurate. that 1% is either new sources or more likely false positives. Hence my council to mark mail appropriately. The filters will never ever learn.

You might have some fun with the junquilla add-on as it exposes details of Thunderbird scorings of junk and allows you to chance the junk threshold as well as creating a possible spam folder to further train the filter.

BAsically the filter log is probably being locked by your anti virus for scanning after ever use, or even on every open so it is only sometimes available for data to be written. This is just one of the reasons we recommend creating an exception in the anti virus for the folders containing the Thunderbird profile. Anti virus just causes too many errors to let them play there any time but when you are doing a full scan and not using the files it spends hours examining.

It is not uncommon for your Thunderbird profile to have a file in excess of 1 Gb. Anti virus products scan at about 1gb per 10 minutes. So the user either gets defective search results or obscure messages about files being local or missing or folder being unavailable. The original programmers actually assumed Thunderbird was on a local disk where there was no delay in accessing files.

I can try to place an exception in Avira.

However, this does not explain why a manual execution of the filter either at filter creation time (click "Execute" on the Message filters panel) or any time after (Tools / Apply the filters on the message or Apply the filters on the folder) leaves a trace in the filter log and no trace while receiving the messages. If the log file were locked by another process, I suppose it would never work.

What would help is if someone could set up a filter with a given tag in the subject for example to move the message to the trash folder, activate the log, then send to him/herself a message with this tag in the subject and check if the log reflects the filter action while receiving the mail. I would then know if this is a problem I have on my PC or of this is a bug in Thunderbird.

Thanks JP

As I understand it, and I am no expert on file open and close, the log would be opened and closed again after each filter decides if it has anything to log so I would be thinking the file may open and close to have something written to it many many times in the reception of a few emails. Emails received times number of filter that applied something type maths.

Now you only ever make a filter when you have something to filter, so you will always get a hit the first time because you have constructed the filter with the express purpose of it applying to a specific mail you have received.

Again manually running a filter will see a long period before the file used is needed for more filters to update it. See if your exception does anything. If not I will try and replicate your results.

Well, if you refer to the "Execute" at filter creation time, maybe it's a matter of 1 isolated action. Concerning the "Tools / Apply the filters to the message" or "Apply the filters to the folder" it is for all defined filters.

I just made this test. I moved 10 mails previously filtered back from the Trash to the Input folder. On the Input folder I clicked "Tools / Apply the filters to the folder". It took 1 minute 50% cpu (456 filters, 3000+ mails) and the 10 messages were moved again to Trash. Filtering works well. And guess what, the log file shows these 10 actions.

I just discovered something... In the filter rule panel, the "Apply filter:" title lists 4 tick boxes. The 2 first are by default ticked ON when defining the filter rule: 1- when manual execution 2- when receiving mail

The 2nd tick box (2- when receiving mail) has a complementary choice: 2.1- Filter before verification of junks (default) 2.2- Filter after verification of junks

I noticed that the log file is actually updated ONLY for option 2.2. I don't think this option should drive the log update, this looks like a bug.

These options are reflected in the rules file "msgFilterRules.dat" into the type="nn" line.

The default options result into type="17". With above 2.2 choice, type="48".

As a workaround to overcome this issue, I changed this in the rule file with Notepad instead of modifying 456 rules 1 by 1 through the interface.

And hopefully, I will be able to use my Excel tool to report and clean up these filters !

please report the bug... https://bugzilla.mozilla.org/

Logged Bug 1366461 Thanks & Best Regards JP