I was trying to regenerate a Silverlight proxy, but I kept getting this error: Turns out, Win 7 sometimes adds an <extendedProtectionPolicy policyEnforcement="Never" /> element to your Web.config. Here’s the workaround according to the Silverlight Web Services team: On Windows 7, when you use the Silverlight-enabled WCF Service item template, an <extendedProtectionPolicy /> element may be generated in Web.config. This element is not supported by Silverlight. Simply remove the element...