I have a client who is using Exchange 2007 at their site and connecting with Outlook for Mac.  When they search for a specific string in the inbox not all messages are displayed.  Once we click "all items" the other messages appear then disappear to never be seen again.  All the messages remain in the user mailbox and are accessible through Outlook Web Access or BES (on his blackberry device) but Outlook for Mac never shows them again in search.  Any ideas?