Archive on Mac only?

Sorry about the late reply on this one. MailMate really is IMAP only and I don't have any current plans to change that. Essentially (if you think about it), “On My Mac” support is the same as supporting POP3. Messages are only temporarily stored on the server.

I'm not going to say “never”, but I'll mark this ticket as bluesky to emphasize that this is far from the top of my list.

That said, MailMate is quite flexible and I believe it's possible to “hack” an “On My Mac” mailbox. This can be done using an offline IMAP mailbox either inside a real IMAP account or inside a dummy offline IMAP account (the latter is probably best to avoid accidentally taking it online). I haven't tried this, but here we go:

• Enable 2.0 features in the General preferences pane.
• Create an IMAP account named “On My Mac”. Set “dummy.example.com” as IMAP server name and a “dummy” username. Click “Add”.
• Select the IMAP account and right-click to do “New IMAP Mailbox in On My Mac”. Name it, e.g., “Local Archive”.
• Also create “Deleted Messages”.
• Also take account explicitly offline (to avoid MailMate trying to connect to the server).
• Double-click the icon of the new “Local Archive” mailbox to open the mailbox editor.
• Go to the “Rules” pane.
• Add a rule which only has actions. First, it should “Copy to Mailbox” with the same mailbox as destination. Then it should move to “Deleted Messages” twice.

That looks a lot more complicated than it is, but the end result should be that you can move messages to “Local Archive” and then they are both moved to this mailbox and deleted on the IMAP server. The strange rule-side-stepping-copy-stuff at the end is because if the messages were simply moved then they would never be deleted from the original IMAP server. MailMate is very careful about never deleting anything server-side until after it is certain that the messages exist on the destination IMAP server. This requires the destination to be online.

When messages are in the offline mailbox then they can be moved into other offline mailboxes without all the side-stepping.

Note that MailMate does not officially support local messages only and if you do the above then don't look at me if you loose messages due to a local crash caused or not caused by MailMate. There is no longer a server backup.

If you try it then please let me know if the above actually works (or not) or if you find a better/cleaner solution.