A user sent a message with a large attachment (772 MB) that fails to transmit (journal) to the archiver and eventually crashes the transport. After the transport recovers and mail traffic resumes, the message eventually re-appears in the queue and the cycle repeats.

How can I prevent the system retrying the transmission of this me

Have you tried deleting the message in the queue viewer?

Yes. And, while we are able to remove it from the queue, we continue to see it return. We've implemented size limits that may help.

Another thing you can do is temporarily shut down or disconnect the Barracuda.  The message should stay in the queue for a couple of days, and then you can catch and delete it.  Be sure to delete it without an NDR or you may end up just sending another message!