Could not load file or assembly 'Newtonsoft.Json' or one of its dependencies. Manifest definition does not match the assembly reference

Question

To solve this, I ensured all my projects used the same version by running the following command and checking the results:

update-package Newtonsoft.Json -reinstall

And, lastly I removed the following from my web.config:

  <dependentAssembly>
    <assemblyIdentity name="Newtonsoft.Json" publicKeyToken="30ad4fe6b2a6aeed" culture="neutral" />
    <bindingRedirect oldVersion="0.0.0.0-6.0.0.0" newVersion="6.0.0.0" />
  </dependentAssembly>

If you want to ensure all your Newtonsoft.Json packages are the same version, you can specify the version like so:

update-package Newtonsoft.Json -version 6.0.0 -reinstall

I am using Newtonsoft.Json v6.0.3, but this is what I had to do in my Web.config file:

<dependentAssembly>
        <assemblyIdentity name="Newtonsoft.Json" publicKeyToken="30ad4fe6b2a6aeed" culture="neutral" />
        <bindingRedirect oldVersion="0.0.0.0-4.5.0.0" newVersion="6.0.0.0" />
</dependentAssembly>

Note that even though I am using 6.0.3, I had to put in newVersion="6.0.0.0"

In my packages.config file I have:

<package id="Newtonsoft.Json" version="6.0.3" targetFramework="net45" />

I tried the following after having already ensured that my computer had the same version in all locations and that my projects were all pointing to the same reference path. I had also made sure that the binding of the old version was their and bound to the current version of dll that I had.

I work in an environment with a strict framework and the framework team often upset the versioning with the different dll's.

How I fixed this issue was to run the package manager console within visual studio (2013). From there I ran the following command:

update-package Newtonsoft.Json -reinstall

followed by

update-package Newtonsoft.Json

This went through and updated all of my config files and relevant project files. Forcing them all to the same version of the dll. Which was initially version 4.5 before updating again to get the latest.

I had the same error message and, like you mentioned, it was due to different versions of the Newtonsoft.Json.dll being referenced.

Some projects in my MVC solution used the NuGet package for version 4 of that dll.

I then added a NuGet package (for Salesforce in my case) that brought Newtonsoft.Json version 6 with it as a dependency to one of the projects. That was what triggered the problem for me.

To clean things up, I used the Updates section in the NuGet Package Manager for the solution (off Tools menu or solution right-click) to update the Json.Net package throughout the solution so it was the same version for all projects.

After that I just checked the App Config files to ensure any binding redirect lines were going to my chosen version as below.

<bindingRedirect oldVersion="0.0.0.0-6.0.0.0" newVersion="6.0.0.0" />

Ok, I think I got it to work now. I deleted every Newtonsoft.Json.dll on my machine that wasn't the latest version that I could find, made sure I had the latest version in NuGet, and build it and made sure that was the latest one in the bin folder, and I left the changes in the web.config and the .csproj. Now I'm on to another error, so it must be working..

By commenting it out this part on my web.config solved my problem:

<dependentAssembly>
    <assemblyIdentity name="Newtonsoft.Json" publicKeyToken="30ad4fe6b2a6aeed" culture="neutral" />
    <bindingRedirect oldVersion="0.0.0.0-6.0.0.0" newVersion="6.0.0.0" />
</dependentAssembly>

But of course you need to make sure you have updated or you have the right version by doing this in your package manager console:

update-package Newtonsoft.Json -reinstall

After hours struggling with this... I did the following:

web.config

<runtime>

  <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">

    <dependentAssembly>
      <assemblyIdentity name="Newtonsoft.Json" publicKeyToken="30ad4fe6b2a6aeed" culture="neutral" />
      <bindingRedirect oldVersion="0.0.0.0-12.0.0.0" newVersion="12.0.0.0" />
    </dependentAssembly>

    <!-- other assemblies... -->

  </assemblyBinding>
</runtime>

The key to enter the correct newVersion and oldVersion number is open the project's References find the package go to its properties or click alt + enter

You'll find a section Version which in my case was 12.0.0.0 while its actually 12.0.3 when exploring with Manage NuGet.

So you need to pick the package's version from the reference properties (in my case 12.0.0.0)

Finally, clean and rebuild the project (you might want to delete the bin and obj folders before).

You might face other packages dependencies issues, i did that for all and they worked.