http://blogs.msdn.com/b/duetsupport/archive/2012/01/24/cannot-compile-web-service-proxy.aspxI recently worked an issue where we were getting the following error in SharePoint Designer when trying to create a connection to a WCF Service for a new External Content Type. Connection to the WCF service that has connection name < Name > cannoten-USTelligent Evolution Platform Developer Build (Build: 5.6.50428.7875)