I've turned on the "virtual trash" option in the webmail interface and turned off moving messages to the (real) trash folder. But in this scenario, I can find no way to expunge deleted messages. I would have expected "empty trash" to do it--but that seems to have no effect at all.

Is there no way to do this?

It doesn't sound like it in the Help description;
Virtual Folders: Virtual Trash
Virtual Trash is a saved search that does away with the need for a separate Trash folder. Instead of moving messages to a centralized trash folder, messages are simply marked as deleted in the current folder they live in. When 'show deleted messages' is turned off, this results in these messages not appearing in a mailbox view. When a user clicks on Virtual Trash, *all* mailboxes all searched for messages that are flagged deleted and these messages are displayed in a single mailbox.

Yes, I understand that deleting a message does not actually expunge it. This doesn't directly address whether an expunge operation is available. Though I'm beginning to think that it's not. I also can't find the "show deleted messages" option anywhere. Being able to turn that off would make this configuration a little more usable. (Assuming that, at some point, the deleted messages are actually expunged somehow rather than allowed to fill up storage indefinitely.)

To phrase this another way, there doesn't seem to be a way to empty the trash in this configuration. If, under "Login Tasks", I configure it to purge trash at every login, logging out and back in does not change the contents of the virtual trash folder.

That's the stuff I highlighted in red. .. simply marked as deleted ...

As above, in the Help, there is nothing provided in the software to "automatically" delete stuff from your "virtual folder" configuration.

Correct ... it's the 'actual' Trash Folder that is acted upon .. which we have thus far seemed to have agreed that is not being used due to your configuring for a 'virtual' trash Folder, which per the Help description, is not a Folder at all.

My reading of the help information is that the Virtual Trash option uses the IMAP process which simply marks a message as deleted and then hides that message so that it appears to be gone when, in fact, it is simply marked by IMAP as deleted.

You would still need to remove the deleted message by another means for them to be entirely gone. The 'expunge' option would be the equivalent of moving to the physical trash folder. There isn't a single button to do this although it MAY be possible to do it with a filter. I haven't tried.

For that reason I can't think of why you'd not simply use the standard trash folder. But, of course, you may have a good reason I can't think of.

Andrew

Er... again, I'm fully aware of the extent of the delete operation's function. I'm not suggesting that "delete" should do something different; I'm looking for an "expunge" operation. This is common in IMAP clients. Sometimes it's called "compact".

Actually, that seems not to be quite true. Using quick reporting appears to perform the expunge operation as a side effect.

My reason is, "I also use another IMAP client with this account that uses a 'virtual' trash folder, so I'm looking to achieve consistent operation between the two."

This, of course, means that I can do the expunge from the other client. It's just such a common operation that I'm surprised to find it unavailable in the webmail interface.

That's an interesting discovery... Are you saying that when you quick report the virtually deleted items that they are removed? That's expected since a quick report moves the reported item to the real trash folder after the spam report is submitted. But, of course, you will not want to report all the deleted items unless they are also spam items. So I'd say that quick reporting virtually deleted items isn't a helpful means of cleaning out the virtual trash unless you only delete spam.

Andrew