Mail.app stops receiving mail from exchange server
mail.app under mac os x 10.6 sometimes stops receiving new mail from exchange server.
how it manifests: things might work smoothly for a while (weeks at a time). then i might notice i haven't received new mail for a while via my exchange account. or i might see some new messages on my iphone that don't show up in mail.app. when this happens, it is not obvious from within mail.app that there is anything wrong - no error is reported. mail.app acts and appears as though it is still connected to the server and is checking for mail, however no mail appears.
i try a forced "synchronize" command from the mailbox menu. that seems to run successfully, but does not resolve the problem (missing mail still does not appear).
a key observation: if i simply quit mail.app and then immediately restart the app without changing anything else, then i see all mail and everything goes back to working normally.
the enterprise server in question serves a large enterprise (thousands of users) and is run by a major university. i'm pretty sure that what i'm observing is not a system-wide outage. other people (the majority running other mail clients on windows or perhaps running mac outlook) do not seem to be affected at the same time, though it's hard to be sure about this.
anyone observed this? any ideas what causes it or how it can be fixed?
Mac OS X (10.6.7)
