Could not load file or assembly System.Net.Http, Version=4.0.0.0 with ASP.NET (MVC 4) Web API OData Prerelease

Visual Studio 2013 has a new feature to take care of this. When you build the app, you should see warnings about different versions of an assembly being referenced. Double click the warning to add assembly binding redirects to the web.config.

See http://msdn.microsoft.com/en-us/library/2fc472t2.aspx for more details.

jeff.eynon notes below that you need to have the web.config checked out (if using TFS source control) to get VS to edit the file automatically. Thanks for the tip!


I made it work by upgrading the WebApi package to the prerelease version using nuget:

PM> Microsoft.AspNet.WebApi -Pre

In order to force the project using the latest version of WebApi, some modifications to the root Web.config were necessary:

1) Webpages Version from 2.0.0.0 to 3.0.0.0

<appSettings>
    <add key="webpages:Version" value="3.0.0.0" />
</appSettings>

2) Binding redirect to 5.0.0.0 for System.Web.Http and System.Net.Http.Formatting

<dependentAssembly>
    <assemblyIdentity name="System.Web.Http" publicKeyToken="31bf3856ad364e35" culture="neutral" />
    <bindingRedirect oldVersion="0.0.0.0-5.0.0.0" newVersion="5.0.0.0" />
</dependentAssembly>
<dependentAssembly>
    <assemblyIdentity name="System.Net.Http.Formatting" publicKeyToken="31bf3856ad364e35" culture="neutral" />
    <bindingRedirect oldVersion="0.0.0.0-5.0.0.0" newVersion="5.0.0.0" />
</dependentAssembly>

I think that's it

PS: Solution highly inspired from WebAPI OData 5.0 Beta - Accessing GlobalConfiguration throws Security Error


I experienced this issue when I tried to update a Hot Towel Project from the project template and when I created an empty project and installed HotTowel via nuget in VS 2012 as of 10/23/2013.

To fix, I updated via Nuget the Web Api Web Host and Web API packages to 5.0, the current version in NuGet at the moment (10/23/2013).

I then added the binding directs:

<dependentAssembly>
  <assemblyIdentity name="System.Web.Http" publicKeyToken="31bf3856ad364e35" culture="neutral" />
  <bindingRedirect oldVersion="0.0.0.0-5.0.0.0" newVersion="5.0.0.0" />
</dependentAssembly>
<dependentAssembly>
  <assemblyIdentity name="System.Net.Http.Formatting" publicKeyToken="31bf3856ad364e35" culture="neutral" />
  <bindingRedirect oldVersion="0.0.0.0-5.0.0.0" newVersion="5.0.0.0" />
</dependentAssembly>