Could not load file or assembly Newtonsoft.Json

Question

I have an ASP.NET Web App that I opened today in VS 2022 after some time, and I keep getting an error:

[FileLoadException: Could not load file or assembly 'Newtonsoft.Json, Version=13.0.3.0, Culture=neutral, PublicKeyToken=30ad4fe6b2a6aeed' or one of its dependencies. The located assembly's manifest definition does not match the assembly reference. However in the Nuget Package Manager window, I see : Newtonsoft.json, installed: 13.0.3 and in web.config, I see: <dependentAssembly>   <assemblyIdentity name="Newtonsoft.Json" publicKeyToken="30ad4fe6b2a6aeed" />  <bindingRedirect oldVersion="0.0.0.0-13.0.0.0" newVersion="13.0.3.0" /> </dependentAssembly>
I also tried: <dependentAssembly>   <assemblyIdentity name="Newtonsoft.Json" publicKeyToken="30ad4fe6b2a6aeed" />  <bindingRedirect oldVersion="0.0.0.0-13.0.0.0" newVersion="13.0.0.0" /> </dependentAssembly>
I have been searching on this for an hour and all results say to check the things I have already checked. Does anyone have any suggestions?    Thanks in advance for any and all help!

Answer 1

Hi @John Straumann,

You are getting this error probably because this assembly does not match the request.

You can try running the command "Update-Package -reinstall" and cleaning the solution to do a full rebuild.

Note: To open the PMC in Visual Studio, click Tools -> Nuget Package Manager -> Package Manager Console.

Or delete the contents of the project's bin folder and rebuild the solution.

Best regards,
Lan Huang

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