You've accidentally deleted a message permanently and you don't see it listed when you go to Tools > Recover Deleted Items. What do you do? Well, if you're on Exchange 2003, there's a little workaround through Outlook Web Access (OWA).
1. Use this address as a model: https://ServerName/exchange/Username/inbox/?cmd=showdeleted
Change "ServerName" to the name of your exchange server and "Username" to the user account you're trying to recover deleted items from. You can also change "inbox" to any folder you have on your mailbox, such as Sent Items and Calendar.
2. Log in with the user's credentials.
3. Check the box next to the message(s) you need to recover and click "Recover."
4. Messages should start appearing in Outlook and on OWA.