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 184.108.40.206