.NET project, hundreds of version conflicts and no idea where they are from

We have a .NET solution made of 5 projects; 3 of them are 'standard libs' we use everywhere and are product specific.

When I compile with detailed logs, I see hundreds of conflict errors.

So I simplified things to the first two project and I still get a lot of lines like this:

Encountered conflict between 'Reference:System.IO, Version=, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a, processorArchitecture=MSIL' and 'Reference:System.IO'. Choosing 'Reference:System.IO' because AssemblyVersion '' is greater than ''.

Lib 1 doesn't directly refer System.IO; Lib 2 refers it and has version

So, I guess that Lib 1 indirectly depends on System.IO. After looking at references, it turns out that System.IO.Filesystem depends on System.IO, but from an older version.

The real question is if these errors can cause problems? there is a massive amount and since we're constantly in nuget versioning hell with the shared libs, and always have to remove the references in app.config to get anything to compile, I am curious if this is something I should look more into or not.

I am assuming the app.config is there to remap one version to another, but with shared code it really fails horribly.