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

Find the broken project and right click, Unload, right click, Re-load. Fastest fix for me.

If you get the problem while using the CLI, try doing nuget restore instead of dotnet restore as that sometimes pulls down packages that the dotnet CLI seems to miss.