Could not load file or assembly or one of its dependencies. The located assembly's manifest definition does not match the assembly reference.

PROBLEM: Received the below error at runtime:

{"Could not load file or assembly 'Newtonsoft.Json, Version=4.5.0.0, Culture=neutral, PublicKeyToken=30ad4fe6b2a6aeed' or one of its dependencies. The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040)":"Newtonsoft.Json, Version=4.5.0.0, Culture=neutral, PublicKeyToken=30ad4fe6b2a6aeed"}

SOLUTION: Lots of potential answers here: http://stackoverflow.com/questions/22507189/could-not-load-file-or-assembly-newtonsoft-json-version-4-5-0-0-culture-neutr

But for me the problem was I had a solution with multiple projects, each with different versions of the nuget package. Obviously only one version can be deployed and if it an old version that gets deployed a binding redirect isn't going to help - so in my case I had to upgrade each project to use the same version of the nuget package - note there is a new feature (which I didn't use) that can help manage one nuget package across multiple projects in a solution (https://artczernecki.wordpress.com/2015/09/08/consolidating-package-versions-with-visual-studio-2015-nuget-package-manager/ and http://stackoverflow.com/questions/34022454/nuget-consolidate-vs-update).

Note, this problem reared its head again briefly after I pulled a different branch via github... I think in that case it was an issue with Visual Studio cache files (*ResolveAssemblyReference.cache) found in the obj folder of the projects... closing the solution and re-starting Visual Studio was enough to refresh these and fix the issue.

INTERESTING SIDE NOTE: Nuget package versions are not necessarily the same as the dll AssemblyVersion (the important version - this is what the compiler cares about and is the version number that is important for binding redirects etc - can view in Visual Studio under properties where it is referenced or can use ILSpy or similar) or AssemblyFileVersion (what you see when you right click and view a DLLs properties in explorer - compiler never refers to this).  As an example... Newtonsoft.json nuget package 5.0.2 has a AssemblyVersion 4.5.0.0 and AssemblyFileVersion 5.0.2.16008 ... some more reading is here: http://stackoverflow.com/questions/64602/what-are-differences-between-assemblyversion-assemblyfileversion-and-assemblyin and http://stackoverflow.com/questions/11965924/nuspec-version-attribute-vs-assembly-version