Microsoft Lync 2010 Group Chat requires the following software:

• Microsoft .NET Framework 3.5 SP1
  
  
• Microsoft Visual C++ Runtime 2 (versions 2.0.50727.761 and earlier are not supported)
  
  

If Visual C++ Runtime 2 is not present on the computer, the Lync 2010 Group Chat installation program installs it during installation. If .NET Framework 3.5 SP1 is not on the computer, you are prompted to download and install it before proceeding.