In the Windows 8 mail app, the displayed messages are not properly synced with the IMAP server. In particular, if I use another mail client (e.g. Thunderbird) to delete or move a message from my Inbox, the message remains in my Inbox in Windows 8 mail. This is not how IMAP is supposed to work. Each client should display the current state on the server.

Despite today's update to the Windows 8 Mail App, syncing of IMAP accounts is still not working properly.

When I delete (or move) a message using another IMAP client, the message remains in the original folder in the Windows 8 App.

Some syncing is improved: messages that are read using another client now appear as read in the Windows 8 client (and vice versa).

But IMAP mail is supposed to reflect the state of the server at all times. This is the main point of IMAP (all clients see the same content), and why it is so much better than POP (IMHO).

In my case, in my Thunderbird client on my main computer, I have spam (and other) filters set up on my Inbox. These filters actually move the messages on the server (as an IMAP client should). But if the Windows 8 app sees them before they are moved, then they remain in my Inbox on the Windows 8 App.