I will make a few comments, - if you wish to keep the mailing lists appearing within the account, you could create folders in the IMAP account, and change your filter to COPY to the folders, and then delete from the server. That eliminates the need for local folders. The folders would appear under the account name, and not under unified, so you could untick the account from inbox if there are other accounts you wish to view. - thunderbird knows local folders because the user creates them there. no magic.

David...

...thank you, but sadly, that doesn't do the trick.

I created an 'mlist' folder in the account's inbox and changed the filter to do a copy and then delete, as you suggested.

Unfortunately, this creates an 'mlist' folder on the IMAP server, and then uploads copied email to that and deletes the original from the IMAP inbox. This leaves 2 copies on the IMAP server, which is 2 more than I want !

So what I want is:

 1. for the mailing list email to disappear from the IMAP server altogether, 
     once it has been downloaded by my Thunderbird machine.

     I get that when the filter rule moves stuff to a Local Folder. 

 2. for the mailing list's Local Folder to appear in the account's inbox.

     But even though it looks like this is possible (in the 'Saved Search 
     Properties'), this is impossible... or, at least, I haven't found a way
     to do it.

Chris

I tested this with different results. The incoming message was copied to a folder and the original was deleted, leaving the inbox with one fewer message, and the subfolder with the new message. There was no upload. That would only happen if your filter was copying from the local folder This also allows the subfolder to appear within the account and not within local folder.

David

I tried again. Same result. When I look at the IMAP server (using webmail) I see email has been copied to the mailing list folder and there's also a copy in the 'Deleted Items'.

I have an an account called 'gmch.uk-IMAP', which in the 'All Folders' view is:

 [A] gmch.uk-IMAP               [A] being the Account icon
    [I]   Inbox                           [I]   being the Inbox icon 
    [D] Drafts
    [S] Sent
    [J] Junk E-mail
    [D] Deleted Items
    [F] netfilter                       [F] being the Folder icon

The message filter for 'gmch.uk-IMAP' spots the netfilter@vger.kernel.org address and does 'Copy Message to' 'netfilter on gmch.uk-IMAP' followed by 'Delete Message'.

Could there be something in the account settings which would make the difference ?

Thanks,

Chris

I don't understand. Your post indicates that my suggestion is working. What am I missing?

David...

... perhaps what you are missing is: I want the mailing list emails to be removed from the IMAP server, *entirely* -- so that they only exist only on my laptop (once downloaded by Thunderbird).

What I get is, for each netfilter mailing list email:

1. Thunderbird make a copy in its 'netfilter' folder, and that is then copied up to the server's 'netfilter' folder. Unsurprisingly, the client and server are kept in sync.
2. Thunderbird deletes the original from the Inbox, which moves it to the 'deleted' folder at both client and server ends.

So... rather than *no* copies on the server I end up with *two* copies.

When I make the 'netfilter' folder a Local Folder and make the rule a 'Move', then the email does disappear from the server. But the folder is no longer in the Thunderbird Inbox, so:

1. it is far removed from the Inbox in the Folder Pane.
2. (unsurprisingly) Thunderbird no longer treats the email in the folder as belonging to the account, which affects what happens when emails are (a) marked as junk, (b) deleted, (c) archived, (d) ...

There is a related, and perhaps more general, problem with IMAP: archiving. Am I alone in wanting to archive old email on a "main" machine *and* remove it from the server ?

As far as I can see, with Thunderbird this can only be done by archiving to a Local Folder.

But now we run into the same problem: an Archives folder in Local Folders is no longer associated with the account. And what the Unified Folders view does is incomprehensible, but that's another story.

IMHO: the 'Properties' of a folder should include a 'Local' property, or perhaps a 'remove from server' property. This would solve my (particular) problem with mailing list stuff *and* the more general problem of offline archiving of IMAP email-bases.

[Thinking about this as an extension of the 'Retention Policy' for a folder, perhaps it would also be useful to be able to 'remove from server' anything n days/weeks old, while retaining it in the current (client) folder. This would recover space at the server end and remove no longer useful stuff from mobile devices.]

Chris

I do not count a message in trash folder. With the IMAP filter, you have deleted from inbox and stored in the other folder and the filtered folder meets your objective of keeping it within the account. Moving to a local folder removes it from the online account. Those are your choices and that is not unique to Thunderbird. The IMAP account is on the server and the Local Folders are on your computer.

David...

...thank you: the conclusion is that I can have either one of the two things I want, and lump it.

FWIW: this reinforces my more general conclusion that Thunderbird's folder "system" is FUBAR :-(

Chris