Visual Studio 2013, C#. I have created a Universal app. Using NuGet, I want to add "NTS Topology Suite". When I do the search for the package, at the Solution level, it does not find it, the same thing when searching to add to the 'Windows 8.1 Phone" project. It does find it and successfully adds it, for the 'Windows 8.1' project in the Universal solution. I added the ' Using' statement in a class in the Shared project, but when building, it asks me if I am missing a using statement, or a reference. What is this saying ? Is this a matter of the NTS package being compatible only with desktop applications and thus even thought it does allow to be installed to the references in the "windows 8.1' project, it is not really applicable in universal apps? In a new solution, if I create a Phone project only, it does not find the NuGet package. If I create a new solution for a "windows 8.1" (not phone\not universal), it does find it.