I recently have come accross a serious issue where as the end user is trying to send large attachments usualy over 6Mb but Under 20Mb and the messeges sit in the outbox of his outlook 2007 client. I am running exchange 2003, and have checked and double checked all the settings to be correct. I have even gone as far as to set a maximum messege size limit to 100Mb, which I know is a bit extreme but I was trying anything possible, it was previously set to 20Mb. I am lost. If the messege is 5Mb it sends with no problem any larger the 6Mb it just sits in the outbox of every mail client on the network, all of which are outlook 2007 and are connected to the exchange server.