I've seen some strange behavior on systems where more than one Exchange server is installed into a site and different LDAP values are being used on one or more of those servers and/or the site container has a different value. Technically this should be OK because we're binding with the LDAP port on the local server we're running with so that should be the only one that needs to change. For some reason, however, sometimes Exchange will revert back to the site defaults even if the "use site default" check box is cleared on our server.
I've been able to reproduce this on occasion in the lab and if I set the site value to what I want and set the local Unity server to use the site default and reboot, the problem always clears. I have a theory that it has to do with other servers being ahead of us in the list of servers in the site (since I can't reproduce it if we're the first one installed in a site or if we're the only one in a site), but that's just a theory and hasn't been confirmed by anyone at MS.
Outside of that I'm not sure why this would be coughing up on you...
Jeff Lindborg
Unity Product Architect/Answer Monkey
Cisco Systems
lindborg@cisco.com
http://www.AnswerMonkey.net (new page for Unity support tools and scripts)
