The first thing you should try is setting Outlook offline, then wait about 5 minutes or so before trying to delete the stuck message. If there is an invisible message Outlook keeps trying to send, see Delete Stuck Read Receipts using MFCMAPI for the steps needed to delete the hidden stuck message. The solutions on this page are for messages you can see in your Outbox. The first two methods are the easiest and either should work for most users. We have three methods listed below that can be used to remove the stuck message. If you try to open it (to remove attachments) or delete it, an error will say that Outlook has begun transmitting the message. The /r switch lets you make a test run to see the changes that ExProfRe will make without actually making the changes.If you attempt to send a message that is too large for your mail server you may be unable to delete it from the Outbox. You can use the /v and /r switches to turn on verbose logging and ExProfRe's read-only mode, respectively. To run the tool, you must specify the target Global Catalog (GC) server, or you can use a variety of switches to control the changes the tool makes. Removes or allows renaming of objects that might no longer be valid, such as users' favorite and most-recently opened files.Retains the offline folders file (.ost) for Outlook 2003, but removes and recreates it for older clients.Resets the Offline Address Book (OAB) so that a new version will be downloaded from the new mail server.

Updates the X.400-style distinguished name (DN) of the profile with the correct mailbox server.( ) via a logon script or Group Policy Object (GPO) to redirect an Outlook client to the new mailbox server. Microsoft Exchange Server 2003 Service Pack 1 (SP1) introduced the ability to simply move mailboxes between administrative groups and to enable a similar level of profile redirection. Therefore, you need to manually reconfigure the client's new mailbox location. If a mailbox is moved between servers within an Administrator group, the normal Messaging API (MAPI)-referral mechanism that would tell the Outlook client where the mailbox is now located doesn't function.

Outlook profile cleanup tool