Null reference pointer was passed to the stub when not debugging with IE

Question

In VS2012, my web project debugs fine like always. I use IIS Express. Today, I installed VS 2013 and when I press F5 to debug, I get

Answer 1

The answer was given by @ScottG in his edit, but here's a clearer explanation:

Open your Web Project Properties settings, click the Web tab, and under 'Debuggers,' unclick 'Silverlight.' Obviously, if you're needing to debug silverlight another solution will have to be found, until the VStudio team fixes this bug.