You make some changes in Microsoft Office Communications Server 2007 R2 Group Chat Server. If you make lots of changes or if the changes are made to a group that has lots of members, it may take a long time to process the changes after you restart Group Chat Server. Example: You delete a user from a group in Group Chat Server. The group has lots of users who can access a chat room. If you restart Group Chat Server, the user can still access the chat room for a long time.
The Group Chat Server maintains a cookie of the last known Active Directory changes from a domain controller. When Group Chat Server starts, it binds to the domain controller. Group Chat Server can bind to multiple domain controllers over time and have multiple cookies. If Group Chat Server is restarted, it may bind to a domain controller which cookie is not up to date. Because of this, Group Chat Server has to process lots of changes.
To resolve this problem, install the following update rollup:
980042 getKB -TRACKING: Update for Group Chat Server 2007 R2 - March 2009 (GCS_2007R2_CU5)
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.