Looking for the solution. Yes you are at the right place. Once I also faced the same issue when I was working on a MVC project, I got the error states that “The located assembly’s manifest definition does not match the assembly reference” .
When I ran the solution I saw the YSD (yellow screen of death) that simply gave me the assembly name which is causing the issue.
Could not load file or assembly ‘System.Web.Optimization, Version=126.96.36.199, Culture=neutral, PublicKeyToken=31BF3856AD364E35’ or one of its dependencies. The located assembly’s manifest definition does not match the assembly reference. HRESULT: 0x80131040
In my case I have several MVC projects referring to “System.Web.Optimization” , but I’m getting this issue only in newly added project. When I investigated the issue I found that the project referring to the higher version of “System.Web.Optimization”. This is because the dll has been included using nuget and nuget always downloads the latest version of dll.
FYI: The Microsoft.Web.Optimization package is now obsolete. With ASP.NET (MVC) 4 and higher you should install the Microsoft ASP.NET Web Optimization Framework.