title: Netstandard1.x Nuget packages cannot be installed for netstandard1.x projects
body: <p>After doing a fresh Windows 10 installation along with latest Visual Studio 2015, netcore, and nuget tooling - I can no longer install Nuget packages to any .netstandard projects. Here's some example output:</p>
  
  <pre><code>Restoring packages for 'ClassLibrary1'.
  Restoring packages for c:\users\zone1\documents\visual studio 2015\Projects\ClassLibrary1\ClassLibrary1\project.json...
  Package System.ComponentModel.EventBasedAsync 4.0.11 is not compatible with netstandard1.3 (.NETStandard,Version=v1.3). Package System.ComponentModel.EventBasedAsync 4.0.11 supports:
    - monoandroid10 (MonoAndroid,Version=v1.0)
    - monotouch10 (MonoTouch,Version=v1.0)
    - net45 (.NETFramework,Version=v4.5)
    - netcore50 (.NETCore,Version=v5.0)
    - netstandard1.0 (.NETStandard,Version=v1.0)
    - netstandard1.3 (.NETStandard,Version=v1.3)
    - portable-net45+win8+wp8+wpa81 (.NETPortable,Version=v0.0,Profile=Profile259)
    - win8 (Windows,Version=v8.0)
    - wp8 (WindowsPhone,Version=v8.0)
    - wpa81 (WindowsPhoneApp,Version=v8.1)
    - xamarinios10 (Xamarin.iOS,Version=v1.0)
    - xamarinmac20 (Xamarin.Mac,Version=v2.0)
    - xamarintvos10 (Xamarin.TVOS,Version=v1.0)
    - xamarinwatchos10 (Xamarin.WatchOS,Version=v1.0)
  One or more packages are incompatible with .NETStandard,Version=v1.3.
  Package restore failed for 'ClassLibrary1'.
  </code></pre>
  
  <p>I created the project ClassLibrary1 as a portable class library, change the target to netstandard1.3, and cannot install any Nuget packages that show support for netstandard1.3. Same goes for netstandard1.5 and the other versions.</p>
  
  <p>I just trying pulling and building the source for <a href="https://github.com/jstedfast/MailKit">MailKit</a> (a project that supports .netstandard) to verify I wasn't setting up my project wrong and am getting the same problem:</p>
  
  <pre><code>Errors in C:\Users\zone1\Repos\MailKit\MailKit\MailKit.CoreFX.xproj
      Package System.Net.NetworkInformation 4.1.0 is not compatible with netstandard1.3 (.NETStandard,Version=v1.3). Package System.Net.NetworkInformation 4.1.0 supports:
        - monoandroid10 (MonoAndroid,Version=v1.0)
        - monotouch10 (MonoTouch,Version=v1.0)
        - net45 (.NETFramework,Version=v4.5)
        - netcore50 (.NETCore,Version=v5.0)
        - netstandard1.0 (.NETStandard,Version=v1.0)
        - netstandard1.3 (.NETStandard,Version=v1.3)
        - portable-net45+win8+wp8+wpa81 (.NETPortable,Version=v0.0,Profile=Profile259)
        - win8 (Windows,Version=v8.0)
        - wp8 (WindowsPhone,Version=v8.0)
        - wpa81 (WindowsPhoneApp,Version=v8.1)
        - xamarinios10 (Xamarin.iOS,Version=v1.0)
        - xamarinmac20 (Xamarin.Mac,Version=v2.0)
        - xamarintvos10 (Xamarin.TVOS,Version=v1.0)
        - xamarinwatchos10 (Xamarin.WatchOS,Version=v1.0)
      One or more packages are incompatible with .NETStandard,Version=v1.3.
  </code></pre>
  
  <p>I've posted some more details here: <a href="https://github.com/NuGet/Home/issues/3433">https://github.com/NuGet/Home/issues/3433</a></p>
  
  <p>This all worked before I reformatted with a fresh Windows installation. Am I missing something? </p>