nuget dll is used by another process

I have the error from below and I'm quite out of ideas how to solve it. Tried the following until now:

1. Clean bin/obj/packages/packages cache
2. Remove manually from csproj and packages files the package and add it afterwards..still error
3. Update Visual Studio 2017
4. Reinstall Visual Studio 2017
5. Trace which processes are using a file with name that contains Newtonsoft
6. Copy the solution from another laptop where the builds works just fine

Yet, after all from above, I still get:

Error       NuGet Package restore failed for project DriversApp.Android: Unable to find version '10.0.3' of package 'Newtonsoft.Json'.
  C:\Program Files (x86)\Microsoft SDKs\NuGetPackages\: Package 'Newtonsoft.Json.10.0.3' is not found on source 'C:\Program Files (x86)\Microsoft SDKs\NuGetPackages\'.
  https://api.nuget.org/v3/index.json: Error downloading 'Newtonsoft.Json.10.0.3' from 'https://api.nuget.org/v3-flatcontainer/newtonsoft.json/10.0.3/newtonsoft.json.10.0.3.nupkg'.
  The process cannot access the file 'C:\Users\user\.nuget\packages\newtonsoft.json\10.0.3\lib\netstandard1.0\Newtonsoft.Json.dll' because it is being used by another process.
. Please see Error List window for detailed warnings and errors.                

How to get this solved? I got really stuck on this one...