Consider the following scenario:
You use Microsoft Office Communicator and Office Communications Server 2007 R2, Group Chat in the same environment.
The Instant Message (IM) feature is disabled in your Office Communicator.
You log off the Group Chat client. However, you do not log off the Office Communicator client.
In this scenario, your presence status indicates that you are still online to other Group Chat users.
To resolve this issue, install the following cumulative update:
2491979 Description of the update for Office Communications Server 2007 R2 Group Chat client: March, 2011
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
After you apply this hotfix package, a No IM string is added to your contact information in the participant list of a Group Chat client in the scenario that is described in the "Symptoms" section.
Note This function is enabled when the EnableEnhancedPresence policy is enabled.