title: The type or namespace name 'Json' does not exist in the namespace 'System' (are you missing an assembly reference?)
body: <p>I am using .NET Framework 4.5 and I'm having this issue. 
  <strong>The type or namespace 'Json' does not exist in the namespace 'System'</strong></p>
  
  <p>So, I tried to Install-Package System.Json -Version 4.0.20126.16343 but I had this issue afterwards.</p>
  
  <p>The type 'System.Uri' is defined in an assembly that is not referenced. You must add a reference to assembly 'System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089'</p>
  
  <p>Source: <a href="https://www.nuget.org/packages/System.Json" rel="noreferrer">https://www.nuget.org/packages/System.Json</a></p>
  
  <p>Any ideas would be really appreciated!</p>