Question:
Is it normal for items to remain in my mailbox resource even after I retrieve all my messages from the server on Exchange 5.5?
Answer:
Your mailbox “items” include all items in all folders. That includes Sent Items, Deleted Items, Calendar, Contacts, Inbox, and others. You don’t give any details about your configuration, but I wouldn’t be at all concerned about still seeing items in a server mailbox after you think you’ve “retrieved” them all.