Forgive me if this isn't the proper place to post, seemed most fitting. Having a problem where Message Tracking on the Exchange server tells me a message is delivered to the client but it is not being received by the user's Outlook. This happens about once a week (that we know of) and there are no clear indicators as to why it is not getting there. No rules are stopping it or putting it in junk mail. Any ideas on what is causing it or how I can track it down? Could it be an Outlook/OST issue? Server is Exchange 2007, Outlook client is 2007, user mailbox size is about 8 GB. User also has a Blackberry device which receives mail via a local BPS server.