Because of various issues we decided to move our Exchange services to a third-party Exchange host and away from our SBS 2003.

 

We can send and receive mail to users of other domains. However, we can't get internal e-mails (using Outlook 2007) to route to their destination on the same domain. Every time a user sends an e-mail they get an undeliverable. The strange thing is that it changes the e-mail prefix abc@xyz.com to their old internal username for the previous SBS Exchange server xxx@xyz.com.

 

How can I get the SBS 2003 to stop trying to handle mail for our domain and switching that e-mail prefix?

Figured it out on my own.

 

Outlook 2007 was running in cached mode. Took it out of cached mode on each workstation, deleted the .nk2 files on each workstation, restarted Outlook, put back into cached mode.

 

This got rid of the old SBS routing that was locked into Outlook from the SBS Exchange server.