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've tried all answers above. For me works only removal and adding the reference again described in the following steps:

1. Open 'References' under the project.
2. Right click on 'System' reference.
3. Click on 'Remove'.
4. Right click on 'References'.
5. Click 'Add Reference...'.
6. From right menu choose an 'Assemblies',
7. In a search field type 'System'.
8. Choose 'System' from the list.
9. Click 'Add' button.
10. IMPORTANT: Restart the Visual Studio.

'System' reference you can replace with any you need.