http://connect.microsoft.com/VisualStudio/feedback/details/8...
I've had issues which I've posted in newsgroups and forums, that have been turned into bug tickets.
Some teams appear better at this than others mind.
* On a new machine (or maybe a new profile, I haven't checked), enable PowerShell's AllSigned option
* Open Visual Studio and open an MVC4 project, bonus points if it's close to the template in terms of installed NuGet packages
* Watch as Visual Studio hangs indefinitely.
This has been reported a number of times to Microsoft, but I don't think it was fixed in Update 4.
What's happening is PowerShell, running inside Visual Studio is prompting for something to do with a signed PowerShell Script, but Visual Studio hasn't loaded enough of the UI to let you accept the warning/prompt.