Ken,

If it was code I should have the same problem across all the machines. Again it's just specific to one XP/Outlook 2003 machine. If I create a new email, enter "abc" in the to: field then click send, the outlook send event runs first before our custom code and notifies me I have an invalid recipient, I fix it and then click send again and my custom code never fires. So it seems whether it's Outlook canceling the send or our custom code canceling the send, the next time the send button is clicked our code is never called again. Let me know if you have any additional insight. Just to reiterate it's specific to a machine. I have 5 machines running xp/Outlook 2003 and 5 running vista/Outlook 2007 and the issue only occurs on one of the xp machines.