‘Newtonsoft.Json’ already has a dependency defined for ‘Microsoft.CSharp’
because NuGet Package Manager (Version 2.8.60318.667) for VS 2012 does not support .NETStandard (Used for Latest Newtonsoft Json Parser Lib. https://github.com/NuGet/Home/issues/3131 I resolve this issue by installing older version of Newtonsoft Json: PM> Install-Package Newtonsoft.Json -Version 9.0.1 More details on: https://github.com/NuGet/Home/issues/5162 .