Could not load file or assembly 'Newtonsoft.Json, Version=7.0.0.0

A lot of things can go wrong and this error message tells you nothing.

But still I am facing the same issue.

Maybe the easiest way will be to try and reinstall the package.

Go to TOOLS > NuGet Package Manager and Select Package Manager Console. Execute the following two commands:

uninstall-package newtonsoft.json -force
install-package newtonsoft.json

If you still get an error after doing this, then what worked for me eventually is that I deleted Json.Net's section from my .config file. Reinstall brings it back if it's not there and apparently you need to delete it. Until there will be a normal solution in the package itself, I'm afraid this manual step is a must. In package manager console again execute:

Update-Package –reinstall Newtonsoft.Json

Also take a look at your .Net version of the projects in your solution.

This is the Microsoft solution with unloading the project.

This can happen if package.config contains 2 same packages name with a different version.

For Example,

<package id="System.Spatial" version="5.6.2" targetFramework="net45" />
<package id="System.Spatial" version="5.6.4" targetFramework="net45" />

Thank You.

I had the same issue and doing the uninstall and reinstall didn't help. At the time I was trying to install the most current version (10.0.3) of Newtonsoft.Json. I ended up installing the 7.0.1 version and then ran across another article that suggested copying that .dll to :\Program Files (x86)\Microsoft Visual Studio 14.0\Common7\IDE. Which I did.

Started the install REST API process again and then received a different error. When attempting to install Microsoft.Rest.ClientRuntime 2.3.2 it failed. For this, I just went into NuGet and had it install to the project in which I was installed the REST API.

Started the REST API install again and this time it installed.

Oh and if it helps anyone with searches, I was doing the Azure Immersion 02-API App tutorial using VS2015 on Windows Server 2012R2.

I had the same issue. I followed ekostadinov's forced uninstall/reinstall steps, but needed to add one extra step:

I was upgrading my Solution to Framework 4.5.2. My old Web.Config file had a namespace in the configuration tag.

<configuration xmlns="http://schemas.microsoft.com/.NetConfiguration/v2.0">

I updated to:

<configuration>

Then the bindingRedirect should work for whatever version of NewtonSoft you are using:

<runtime xmlns="">
  <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
    <dependentAssembly>
      <assemblyIdentity name="Newtonsoft.Json" publicKeyToken="30ad4fe6b2a6aeed" culture="neutral" />
      <bindingRedirect oldVersion="0.0.0.0-11.0.0.0" newVersion="11.0.0.0" />
  </dependentAssembly>
</assemblyBinding>