I used the GitHub extension of Visual Studio 2015 to clone my project onto a new computer. I try to restore packages and I get an error that says:
NuGet Pa
Based on your error message looks like you are looking for a version that no longer exists and cannot tell which Package source you have selected. I feel like you are looking for version 2.0.0 which is not available in nuget.org repository. The latest one is 2.0.0-rc and it is pre release candidate.
Please try this command if you want to get the latest version
Install-Package -Id Microsoft.Net.Compilers -Version 2.0.0-rc -Source nuget.org
If you want the latest stable version (1.3.2), try this command
Install-Package -Id Microsoft.Net.Compilers -Version 1.3.2 -Source nuget.org
UPDATE If the package still cannot be installed, then that package may be out of sync between packages.config, packages/ folder and .csproj file
Please follow these steps to perform manual cleanup
Some of the entries that you may have to remove from .csproj as part of step 2 are these
This project references NuGet package(s) that are missing on this computer. Use NuGet Package Restore to download them. For more information, see http://go.microsoft.com/fwlink/?LinkID=322105. The missing file is {0}.