Debugging VS2013/VS2015 Websites Using 64-bit IIS Express

If you are working on ASP.NET MVC web sites in Visual Studio 2013 (VS2013) or 2015 (VS2015), and want to debug 64bit application, you need to do following changes in Visual Studio.

f you don?t do this, you will likely get a message similar to:

?Could not load file or assembly or one of its dependencies. An attempt was made to load a program with an incorrect format.?

For Visual Studio 2013 and Visual Studio 2015:

Tools
  -> Options
   -> Projects and Solutions
    -> Web Projects
     -> Check "Use the 64 bit version of IIS Express for web sites and projects"`