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

Question

Close Visual Studio. Delete the <ProjectName>.v12.suo file. Reopen solution.

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.

Tools > Options > Text Editor > C# > General

Make sure that "Auto List Members" is checked

I have found one way to solve the problem. That is, 1. -> Remove the ASP.NET MVC Project from Solution, 2. -> Then, add the MVC Project back to the Solution.

By doing these steps, I can get the Intellisense again. But, I am not happy with this solution though, because, next time when I double click the Solution file to open the solution, I see the intellisense is not working again. I would like to know the real reason why it is behaving like that.

EDIT:

Finally, I figured out that it was a 3rd party visual studio extension which was causing the problem. In order to find out that extension, I removed all extensions and then, added the extensions one by one and stopped where I found the culprit extension that was taking my sleep away :).