http://blogs.technet.com/b/praveenh/archive/2013/01/15/issue-found-with-net-framework-3-5-1-security-update-kb2756920.aspxAfter installing the update KB2756920 on a Windows Server 2008 R2/Windows 7 RTM  computer running SharePoint Server 2010 with previously installed hotfixes for .NET 3.5 SP1. on the server, the following exception is thrown when any WCF service isen-USTelligent Evolution Platform Developer Build (Build: 5.6.50428.7875)