In AD if you go to the exchange General Tab. You go into the deliver restrictions button it has the option to us default limits for this particular user. Where do you set these limits at? I thought it was in the system manger under Global settings then message delivery and defaults. I changed these settings and it overrode any settings I had setup for the specific user in AD delivery restrictions tab. I was set to be able to send 15mb or recieve 15mb in AD. When I changed the global settings default, I was no longer able to send large attachments.