JObject.ToString `MissingMethodException` when app built against Newtonsoft.Json 13.0.4 loads 13.0.3 from GAC

[nicholas-renaud]

Applications compiled against Newtonsoft.Json 13.0.4 can fail at runtime if version 13.0.3 is installed in the Global Assembly Cache (GAC).

Because both 13.0.3 and 13.0.4 use AssemblyVersion = 13.0.0.0, the CLR will load the 13.0.3 assembly from the GAC even when the application was compiled against 13.0.4. This results in missing members at runtime.

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Steps to Reproduce

1. Install Newtonsoft.Json 13.0.3 into the GAC:

   gacutil /i Newtonsoft.Json.dll (13.0.3)

2. Create a project that references NuGet package Newtonsoft.Json 13.0.4.
3. Use the following code:

   using Newtonsoft.Json;
   using Newtonsoft.Json.Linq;
   
   var jObject = JObject.Parse("{'fieldName':{'fieldValue':'innerObjectValue'},'anotherField':'anotherValue'}");
   jObject.ToString(Formatting.None);

4. Build and run the project on the machine with 13.0.3 in the GAC.

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Expected Behavior

The application should load the version it was compiled against (13.0.4) and successfully invoke the ToString overload.

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Actual Behavior

The runtime loads Newtonsoft.Json 13.0.3 from the GAC, and the following exception occurs:

System.MissingMethodException : Method not found: 
'System.String Newtonsoft.Json.Linq.JToken.ToString(Newtonsoft.Json.Formatting)'

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Notes

• The issue is triggered by the fact that the AssemblyVersion remains 13.0.0.0 across these patch releases.
• Since the GAC version takes precedence, applications compiled against 13.0.4 cannot safely run when 13.0.3 is present in the GAC.

[FollowerOJ]

Having the same Issue here. Any update how to resolve this?

[Powlinz]

Same problem we use Dell laptop at work and our administrator use the app "Dell Command | Monitor" and it's deployed on the entire Dell computers. This app install version 13.0.1 in the GAC and the GAC has priority when loading a dll, so newer version of the dll in our app folder or bin are ignored.

[JamesNK]

This issue is caused by adding a new method overload that's only present in 13.0.4.

A way to work around this problem is to force specify the existing ToString(Formatting, params JsonConverter[]) overload:

using Newtonsoft.Json;
using Newtonsoft.Json.Linq;

var jObject = JObject.Parse("{'fieldName':{'fieldValue':'innerObjectValue'},'anotherField':'anotherValue'}");
jObject.ToString(Formatting.None); // before, broken
jObject.ToString(Formatting.None, new JsonConverter[0]); // after, fixed

[FelixSFD]

Having the same Issue here. Any update how to resolve this?
@FollowerOJ

Depends on how your program got to use the old DLL. If something in your build process copies the old DLL to your application, you need to fix that. If it's loaded from the Global Assembly Cache (like mentioned in this issue), you need to delete it from there. Is' located at C:\Windows\Microsoft.NET\assembly. In one of the subfolders, there should be a NewtonsoftJson folder. Delete that to fix the issue. You might need to do this via command line that is executed as admin.