Xamarin UWP project is not being built after creating in Visual Studio 2015

Question

I installed Xamarin for Visual Studio 2015 and I created Xamarin.Forms Portable project. After that I have tried to build solution.

But I got an error for UWP project: Error Type universe cannot resolve assembly: System.Runtime, Version=4.0.0.0, in Visual Studio 2015.

What is the problem?

Answer 1

The solution was simple. I installed Mirosoft.NETCore.UniversalWindowsPlatform package via the Package Manager Console:
PM> Install-Package Microsoft.NETCore.UniversalWindowsPlatform

Answer 2

If you have the newest version of NETCore.UniversalWindowsPlatform installed and it still isn't working, make sure that you're using the newest nuget.

We had it working in Visual Studio, but failing in command line. The reason was that we were using old version of nuget.exe, and this caused our F# fake script to use msbuild 14 instead of 15.