This cumulative update improves the reliability, stability, and performance of Lync 2010 & Lync Server 2010.
Lync 2010 Hotfix KB 2953593 (64 bit)
http://www.microsoft.com/en-us/download/details.aspx?id=14490
Lync 2010 Hotfix KB 2953593 (32 bit)
http://www.microsoft.com/en-us/download/details.aspx?id=25055
Lync Server 2010 Hotfix KB 2493736
http://www.microsoft.com/en-us/download/details.aspx?id=11551