Nuget error “Object reference not set to an instance of an object” while installing Entityframework 7 from Package Manager Console in VS2015

Question

I am trying to build a sample application using EF7 and mvc 6 in visual studio 2015 pre release.

While installing both EF7 and MVC6 using package manager console getting

Answer 1

I solved my problem by adding:

https://api.nuget.org/v3/index.json

as a Package Sources feed, as shon on the picture below: