I am running Exchange 2003. Global setting are No Limits for sending and receiving, Mailbox Store settings are all cleared for Limits, subject User mailbox setting on AD account is Use Default. This user was the reciepient of an email with a 6MB attachment that resulted in 5.2.3. It looks to me as though things are wide open on my exchange server and there should be no limits. There is no policy set for limits. This has been stumping me for a while.