Unable to retrieve metadata for ‘models.classname’. unable to cast object of type System.Data.Entity.Core.Objects.ObjectContext to type System.Data.Objects.ObjectContext.

Entity framework 6 or above version is not supported for asp.net MVC. So we need to uninstall it by using Package manager console.

Uninstall-Package EntityFramework –Version 6.0.0

If it is uninstalled then install entity framework 5.

If you are unable uninstall then I recommended you to delete the following entity framework version 6.0.0 reference from package.config.

<package id="EntityFramework" version="6.0.0" targetFramework="net45" />

Again install entity framework 5 by running the following command in the Package Manager Console

PM> Install-Package EntityFramework –Version 5.0.0.0