Could not load file or assembly 'System.Web.Http 4.0.0 after update from 2012 to 2013

Question

I did the upgrade according to. http://www.asp.net/mvc/tutorials/mvc-5/how-to-upgrade-an-aspnet-mvc-4-and-web-api-project-to-aspnet-mvc-5-and-web-api-2

I get the er

Answer 1

I had this from a WCF service. For me (as the issue was displaying in local dev), I simply had to delete the contents of the bin folder under the solution. The the rebuild work fine once again.