Assume that you use Microsoft Lync 2010 to start an instant message conversation with a user who uses Microsoft Office Communicator 2007 R2. When you switch to the Conversation tab in Lync 2010, Lync 2010 displays the Rich Text Format (RTF) header under the Office Communicator 2007 R2 user's name. For example, Lync 2010 might display the following message:
This issue occurs because Lync 2010 cannot handle RTF format conversation history that is used by Office Communicator 2007 R2.
To resolve this issue, install the following cumulative update:
2670326 Description of the cumulative update for Lync 2010: February 2012