A Lync 2010 Group Chat client crashes when you start two instances at the same time Content provided by Microsoft Applies to: Lync 2010 Group Chat Select Product Version All Products Symptoms When you start two instances of a Microsoft Lync 2010 Group Chat client at the same time, a race condition occurs. Additionally, this causes the Lync 2010 Group Chat client to crash. Resolution To resolve this issue, install the following cumulative update:2636065 Description of the cumulative update for Lync 2010 Group Chat client: November 2011 Last Updated: Nov 19, 2011 Did this solve your problem? Yes No Tell us what we can do to improve the article Submit Thanks! Your feedback will help us improve the support experience.