If you have upgraded your MVC3 project to MVC4 running in VS2010, and still targeting the 4.0 framework, you will have problem while running your build as below:

To fix this problem, you need to do the following:

  1. Unload the project in Visual Studio
    2.  Edit the .csproj file

3. Comment out the lines as below:


  4. Reload the project
  5. Re-build and you should see a success build!