I got stuck in this problem every thing going fine for a year until i did a mistake: Microsoft offered a product update so i updated my vs2012 and my nuget package stop installing new packages .
I uninstalled it and reinstalled new one nothing happen i use console package manger to install host file that is missing as error said but nothing happed still giving me error .My Entity framework 5.0 could not be loaded when making new project and some of my old ones are stop working WebApi and MVC 4.5 giving me error of Entity Framework 5.0, jQuery UI, JavaScript Could not be loaded etc i try to install it from nuget package manager but it said could not be installed i search the web for its solution no one give me satisfied answer every one got same prob after updating their update please help