I have a mixed WebForms/MVC web project that worked fine in Visual Studio 2012, but failed horribly when I moved to Visual Studio 2013 Release Candidate.

All of my WebAPI’s stopped working. Apparently there are changes to routing with the latest Visual Studio release. Previously you did not have to manually specify route information if you were using attribute routing, and now you do. It says that more changes are coming too: http://blogs.msdn.com/b/webdev/archive/2013/09/23/attribute-routing-changes-for-asp-net-web-stack-shipped-in-vs2013-rc.aspx