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

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

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

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.

You can solve the issue by adding below lines in web.config file.

 <runtime>
    <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
      <dependentAssembly>
        <assemblyIdentity name="Newtonsoft.Json" publicKeyToken="30ad4fe6b2a6aeed" culture="neutral"/>
        <bindingRedirect oldVersion="0.0.0.0-8.0.0.0" newVersion="8.0.0.0"/>
      </dependentAssembly>
    </assemblyBinding>
  </runtime>

In my case it was just a matter of:

Tools -> NuGet Package Manager -> Package Manager Settings -> Clear Cache

The problem was caused when I remapped a TFS folder.

I have tried the steps by Oleg, and they worked for my same situation.

Steps:

Run update-package Newtonsoft.Json -reinstall in Package Manager. Delete your bin by enabling viewing the hidden files and deleting the bin folder. Close your Visual Studio and re-open it. Now run your project again. I believe it should be ok!

What actually helped me was to turn off the Resharper build and to use the VisualStudio Re-Build option on my project.

from Tools>>NuGet Package Manager>>Manage Package for solution update Newtonsoft.Json of all solutions to latest Version

if you're working with some kind of subversion: delete the project and re-download it, it worked for me :S

I had the same issue on a Test Project that had reference to an MVC 5 project. This happened after I merged with an MVC 5 project. I fixed it by installing Visual studio 2012 updates as explained here in Andre's response.

In your visual studio go to Tools> Extensions And Updates Select "Updates" in the accordion list on the left. Select "Product Updates". Update to the newest version

Tools> Extensions And Updates

Select "Updates" in the accordion list on the left.

Select "Product Updates".

Update to the newest version

I Don't know why, but in my case, even if I remove bin folder from project, when I build project it copies old version of newtonsoft.json, I copied new version's dll from packages folder and It solves for now.

If none of these works, please check this answer:

https://stackoverflow.com/a/12011221/150370

(TL;DR: Remove xml namespace from configuration tag in your config file. Otherwise binding redirects will be ignored)

In some cases if you delete your Bin and Obj folders will solve this problem.

Alright so I guess the thing to do is add my answer here to this long list versus creating a duplicate question...

If you are getting this in 2019, using .NET Core 3.0 (Preview at this time), the solution is to ensure all projects are targeting the same .NET Core version (in my case 3.0). I think I had one project in the solution targeting 2.1 and the rest were 2.2 so I probably could have stuck with 2.2...

I don't even have Newtonsoft.Json installed in any of the projects, and naturally adding it to them did not fix the issue.

If you have .NET Standard class libraries or w/e in your solution, they don't need to be on the same version, though they should probably be the latest you can go. For example, my .NET Standard class libraries are on 2.2 as there is not a .NET Standard 3.0 yet.

None of the answers, including the checked one did not work for me.

The solution was far more simple. I first removed the references from my BUS layer. Then deleted the dll's from the project (to make sure it's gone), then reinstalled JSON.NET from nuget packeges. And, the tricky part was, "turning it off and on again".

I just restarted visual studio, and there it worked!

So, if you try everything possible and still can't solve the problem, just try turning visual studio off and on again, it might help.

I resolved it by remove lower version of Newtonsoft.json.dll in bin folder and added Newtonsoft.json.dll V6.0.0.0 and removed the following web.config elements

<dependentAssembly>
    <assemblyIdentity name="Newtonsoft.Json" publicKeyToken="30ad4fe6b2a6aeed"/>
    <bindingRedirect oldVersion="0.0.0.0-4.5.0.0" newVersion="5.0.8"/>
</dependentAssembly>

I got the same problem with dotnet core and managed to fix it by clearing the NuGet cache.

Open the powershell and enter the following command.

dotnet nuget locals all --clear

Then I closed Visual Studio, opened it again and entered the following command into the Package Manager Console:

Update-Package

NuGet should now restore all packages and popultes the nuget cache again.

After that I was able to build and start my dotnet core webapi in a Linux container.

the solution that solved my problem for this is

goto references->right click Newtonsoft.json--goto properties and check the version

this same version should be in

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

Easy steps. (1)Run "update-package Newtonsoft.Json -reinstall" in package manager.

(2)Delete you bin by enabling viewing the hidden files and deleting the bin folder.

(3)Close your visual studio and re-open it.

(4) Now run your project again. I believe it should be ok

I hit this problem because I had: project A (a desktop .exe) refer to project B (a portable .dll). A & B had different versions of JSON.Net, and so there was a loader conflict. Once I made all the versions of JSON.net the same, it worked. (This is in effect what some of the solutions above are doing - I'm just calling out why it works)

I struggled with this recently with and older project.

I managed to track down the problem after checking what version of the dll that actually was in the bin folder.

I had a post-build script that copied dependent assemblies from a dll library folder to the bin folder. A common setup from the days before nuget.

So every time I built the post-build script replaced the correct version of Json.net with the older one

I had exactly the same issue and Visual Studio 13 default library for me was 4.5, so I have 2 solutions one is take out the reference to this in the webconfig file. That is a last resort and it does work.

The error message states there is an issue at this location /Projects/foo/bar/bin/Newtonsoft.Json.DLL. where the DLL is! A basic property check told me it was 4.5.0.0 or alike so I changed the webconfig to look upto 4.5 and use 4.5.

None of these options worked for me, in the end it was;

Test > Test Settings > *.testrunconfig

I had to add a new line

<DeploymentItem filename="packages\Newtonsoft.Json.4.5.8\lib\net40\Newtonsoft.Json.dll" />

Make sure the path and version is correct for your setup.

I had the same issue. I created a web api project and then upgraded it from .net 4.5.1 to .net 4.6.1. Closing the IDE, stopping IIS, and deleting contents of the C:\Windows\Microsoft.NET\Framework\v4.0.30319\Temporary ASP.NET Files\ dir fixed the issue.

HTH

This problem was not solved for me by refreshing NuGet Packages or by performing a "Clean" on the project. It was solved by clearing out the "obj" folder manually.

Here is my solution to this problem,make sure the version number in appconfig or packageconfig is same as the reference version in your references. See here