I took a ASP .NET 2003 (.NET 1.1) application and converted it to an ASP .NET 2005 (.NEt 2.0) application using the Web Application Projects add-in provided for Visual Studio 2005. That went pretty well and now I am trying to convert the resulting VS 2005 ASP .NET 2.0 appliation to VS 2008 ASP .NET 3.5 and am getting the error. Please note that I am running VS 2008 Professional. Also the solution has two projects a dll and a web. The dll compiles fine but when I try to compile the web I get the error message: "The project file must be opened in the Visual Studio IDE and converted to the latest version before it can be built by MSBuild." Any and all help is appreciated.