It has been a while since you asked this question, but I recently came across a similar problem, except that MVC4 added EntityFramework.5.0.0 to Visual Studio 2012 Ultimate.
The problem was that I was trying to create a project in a network folder (I am running Windows 7 in a virtual machine on top of OSX).
The problem is that the network folder is not considered a trusted location. I needed to go to Control Panel → Internet Options, click the "Security" tab, click "Local Intranet" and click the "Sites" button.
In the popping up Local Intranet dialog box, I turned off Automatic Intranet Network Discovery and check the box "Enable all network paths (UNC)"
Now I assume that Visual Studio and / or nuGet sees the network folder as a trusted location, and EntityFramework.5.0.0 is installed along with everything else, which requires a new MVC 4 project.
The loan belongs to my colleague who handed me this SuperUser post .
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