Visual Studio 2013 IntelliSense stops working for ASP.NET MVC5 Controllers

Question

I am facing a weird problem in my Visual Studio 2013 ASP.NET MVC 5 project. All of a sudden, the IntelliSense in the Controller classes of the MVC 5 project are not working

Answer 1

Resetting my settings or importing previously exported, working settings, and restarting Visual Studio worked: Tools > Import and Export Settings... > Reset all settings.

EDIT: This keeps happening to me, surprisingly often in VS Express, and occasionally in VS Professional. One thing I noticed in Pro, is that it has happened after unexpected shut downs (when IT forces a reboot in the middle of the night). So it may be related to Visual Studio not closing correctly. The technique described above has worked every time.