I have several messages stuck in the exchange 2007 queue that have no "from address" and are in a failed retry state due to "Categorization failed. This message will be deferred and retried because it was marked for retry if rejected".
I do have journaling setup on this machine, an the one common denominator I see is that all of these messages are coming from my Exchange 2003 server.
Prior to this starting I had moved my queue to a new partition (ran out of space), re-created a completely new queue...and have restarted the server. I am going to restart again tonight, but I can't seem to find much info on this problem. It does log an event ID 9213 as well.