I installed SQL Server 2005 in a VM, and started work on a small SSIS demo. I needed to get a quick queue up and running, so I followed the docs, created a dialog, sent a message on that conversation, and…nothing. No message sitting in the receive queue. A check of the sys.transmission_queue revealed this error:

An exception occurred while enqueueing a message in the target queue. Error: 15404, State: 11. Could not obtain information about Windows NT group/user ‘TESTING\Administrator’, error code 0×534.

I was curious about the specific user name there–my VM is a workgroup computer, not part of a domain, and “TESTING” was the old machine name–I renamed it some time ago to “SQLVM”. I checked Security\Logins in the Management Studio, and sure enough–there was “TESTING\Administrator”. A quick right-click, rename to “SQLVM\Administrator”, retried the send, and everything worked.