I ran across this issue today when working with a WCF service project. We had generated a settings file through the project properties and in turn added entries into the web.config transform files for the different deployment modes. The base config and the transform blocks for the <applicationSettings> element were what you would expect: Web.config: <applicationSettings> <Namespace.Properties.Se... <setting name="test" serializeAs="String"> <value>test</value... ......