I have a single user that is not showing up in our Vista machines contact list. She is listed in our XP machines. I can search for her, but when I try to add her I get disconnected from the server. She is in a group that should autopopulate in our client computers contacts. She is showing up on our Server and is in our Vista users rosters. We were able to see her before the weekend and nothing changed that I am aware of.
I will do some more digging, but if anyone has run into this and has a solution that would be great.