I've been using Mac Mail.app and my iPod Touch with Intermedia hosted
Exchange for the last few years with no problems. All of a sudden in
the last few days, there are recent messages that are invisible to
Mail.app on a Mac and on my iPod Touch, but they are visible using
Entourage EWS 2008. I have deleted the account and re-downloaded all
new mail from the server multiple times on multiple Macs (laptop,
desktop) and on the iPod, and the problem persists. Yet when I created
a new identity in Entourage and downloaded all mail from the server, I
could see everything.

That's not all: when I move a visible email message from a folder with
no problems to one of the problematic ones, e.g. "Travel," the message
disappears when the client syncs with the Exchange server!

All messages are intact via OWA (I'm on Exchange Server 2010 with
Intermedia). I haven't lost any mail. However, I often think I haven't
received any mail or can't find recent mail on the client side.

Any guesses or thoughts? Could there be something on the server
causing only Mac Mail and the iPod Mail to be losing these messages?