There was an error running the selected code generator: Could not load file or assembly Microsoft.EntityFrameworkCore, version = 2.0.1.0

I updated the Microsoft.AspNetCore.All to version 2.0.3 and now it does work right.

Go to NugetPackage Manager and update the Microsoft.AspNetCore.All package

For me none of the above solutions worked. I had to add Microsoft.EntityFrameworkCore and Microsoft.EntityFrameworkCore.Design packages even though I have Microsoft.AspNetCore.All package added to my project.

Edit project in VS 2017 and add these lines

<PackageReference Include="Microsoft.AspNetCore.All" Version="2.0.3" /> 
<PackageReference Include="Microsoft.EntityFrameworkCore" Version="2.0.3" />
<PackageReference Include="Microsoft.EntityFrameworkCore.Design" Version="2.0.3" />