We have a large number of solutions in our source control, which all use NuGet packages from a custom source (http://nugetserver/nuget). All solutions restore and build successfully locally within Visual Studio.
Using the new TFS 2015, our build definition looks like this:
The NuGet Installer step is there for us to restore our packages from a custom resource:
There is however no NuGet.exe file in the custom NuGet server directory. As suggested here tried just setting the -source to "https://www.nuget.org/api/v2/". We receive the same error at build whichever source we use: