Thanks for the response. The e-mail never leaves Outlook. The moment I hit send, bam, I get an undeliverable from System Administrator. This happens when I use an e-mail address that I type in manual or use from the cached e-mail addresses. For example, if I attempt to send to rberry@cadcourse.com, ehhhhhhh. If I make it a contact and select it from contacts. No problem. I did "screw up" my Address Book lookups in a stupid attempt by me to clear the cached e-mail addresses for the auto-complete function. Dumb. Since then, this behavior is very strange. There are times that the e-mail address that I enter is actually removed and the e-mail address is "()". I've been working on this for weeks with no success. Thanks for all the help!