In our case, the Transport Service stopped and it's mail.que file grew to 5GB with tons of Temp files for good measure.
1. Deleted the queue file and / or the entire "\program files\Microsoft\Exchange Server\TransportRoles\data\Queue" folder.
2. The Transport Service starts up but then the Queue file growth cycle starts over again. Once it reaches 5GB, the Transport Service stops.
3. Server hasn't had any problems for years until this started 2 days ago. 9/15/16
Read that one condition that can cause this (but open to any and all advice) is that a user may have sent a multi Gig email and its in the store but can't be processed. Theory is new queue's are growing due to this Oversized email and thus crashing Transport Service. Per the title of this post I would like some insight on how to confirm / deny this has happened.
Server does deliver email while the queue file grows (albeit slowly). But nursing this around the clock is no fun..
Sincerely appreciate any ideas of how to diagnose this and get this server fixed.
This is my first post here, apologize if not formatted properly.