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

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 at all.

I have other class library projects in my solution and IntelliSense is working in those class library project files, but the problem is only within the MVC project. Usually these kinds of problems are solved by restarting Visual Studio: not only did I restart Visual Studio, but I also restarted my computer, and the IntelliSense problem is not getting fixed at all.

Are there any other steps that can get me IntelliSense back?

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 :).