C# Error for open AI

Hi,

I am trying to post in open AI but I get the following error

  1. Error (CS0433): The type ‘System.Collections.Generic.List’ exists in both ‘c:\Users\username\AppData\Roaming\Grasshopper\Libraries\System.Private.CoreLib\System.Private.CoreLib.dll’ and ‘c:\Windows\Microsoft.NET\Framework64\v4.0.30319\mscorlib.dll’ (line 170)

please let me know how to avoid this error