Warnings in VS2017 but all fine with VS2015

Question

When load my .NET Frameowrk 4.6.2 solution in Visual Studio 2017, it gives me the following warning:

Severity Code Description Project File Line Suppression State Warning Your project is not referencing the ".NETFramework,Version=v4.6.2" framework. Add a reference to ".NETFramework,Version=v4.6.2" in the "frameworks" section of your project.json, and then re-run NuGet restore. 

Another:

Warning IDE0006 Error encountered while loading the project. Some project features, such as full solution analysis for the failed project and projects that depend on it, have been disabled.   BigData     1   Active 

However, loading in visual studio 2015 is totally fine with the exactly same solution files and structures.

Why is this and how I can solve it?

BTW, from what I read, in the latest updates, project.json is merged back to .csproj, why here it's still recommending something on project.json

Answer 1

I had this show up as an error when building shortly after migrating a solution from vs2015 to 2017, and then also doing some git restructuring. As it turns out, I think git was actually the culprit.

Regardless, manually deleting the bin & obj folders in the affected projects solved it for me. (Clean alone wasn't cutting it.)