System could not be found Visual Studio 2017 ASP.NET Core project

Question

I\'ve installed the newly released version of Visual Studio 2017 and started a fresh ASP.NET Core project targeting .NET Core.

Out of the box, I\'m getting the

Answer 1

I had the same issue, the solution for me was to clear the NuGet cache. Tools > NuGet Package Manager > Package Manager Settings > Clear All NuGet Cache(s)