You cannot receive an instant message when you connect to Office Communications Server 2007 R2 from multiple endpoints

Symptoms

Consider the following scenario:
  • You log on to Microsoft Office Communicator Web Access.
  • You try to log on to Microsoft Office Communicator.
  • When you are logging on to Office Communicator, another user sends an instant message to you.
In this scenario, the instant message may not be delivered.

Resolution

To resolve this problem, follow these steps:
  1. Download and then install the update for Microsoft Unified Communications Managed API Redistributable from the following Microsoft Knowledge Base article:
    976657 Description of the cumulative update for Office Communications Server 2007 R2, Unified Communications Managed API 2.0 Core Redist 64-bit: April 2010

  2. Download and then install the latest update for Office Communications Server 2007 R2 Web Service Provider. To do this, click the following Microsoft website:
    http://go.microsoft.com/fwlink/?LinkId=187420

Status

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.