I am running exchange 5.5 SP3 on a windows NT 4.0 server. The problem is that the inbound mail seems to back up randomly through the day. There are no errors in the event viewer and the Internet mail service continues to run fine. The outbound mail also seems to run fine. I have stopped the internet mail service and moved the items out and restarted the service and the mail seems to flow fine for a while, then it stops. If anyone has experienced this before or can provide any info it would be GREATLY appreciated.