Newtonsoft.Json version 8.0.2 Could not load file or assembly Error

I was fixing some old code in one of my Windows Phone 8 solutions and thought of updating the NuGet packages and was greeted with the same issue.

A comment from StivOstenberg here helped me solve this.

This is what I did:

1. Removed the NuGet package. Just clicked 'Uninstall' from NuGet manager. Make sure to remove it from every project in the solution separately.
2. Clean Solution. Rebuild Solution.
3. Now, remove the using statement from your entire solution! Can be done with a quick find and replace for using Newtonsoft.Json on 'Entire Solution'.
4. Repeat step 2. (Ignore the errors)
5. Add package again from NuGet manager & build (Ctrl+Shift+B).
6. Finally (almost), for every error shown, go to the particular page and add reference again.
7. Repeat step 2 and Run.

There might be some redundant steps, but this is exactly what I did, and it worked. Hope it helps you too.

Make sure there are no conflicting versions of Newtonsoft in a parent assembly!

In a child-assembly I wanted to use Newtonsoft.Json.8.0.3.

Well the StartUp project is an MVC5 web app. There I use the BundleTransformer.Less.X.X.X which had a dependency to Newtonsoft.Json.8.0.2. Upgrading NewtonSoft.Json to 8.0.3 (all the same version now) resolved it for me.