This first happened after running a c++ application in Visual Studio Express 2013, and also happened with Visual Studio Pro 2013. I'm using Windows 8.1 Pro, and the same application runs fine on another computer with Windows 7.
When running with debugging, the application will run fine but VS becomes completely unresponsive. I can kill the process but there is still devenv.exe that cannot be killed. When running without debugging, VS continues to work but it creates an empty command prompt window that cannot be closed or killed on every run.
I had this problem in VS Express 2013 and VS Pro 2013.
The problem remains after reboot and even re-installing VS, even with a new project as a simple Hello World.