Object of type System.Int32 cannot be converted to type System.Web.Security.Cryptography.Purpose

When you open the Sitecore Admin and Try to login you get this error:  

Object of type System.Int32 cannot be converted to type System.Web.Security.Cryptography.Purpose

Well John West has the solution. This blog post explains how you can resolve the Object of type 'System.Int32' cannot be converted to type 'System.Web.Security.Cryptography.Purpose' error that you may receive when you try to access a user interface in the Sitecore ASP.NET web Content Management System (CMS) after installing Visual Studio 2012 or .NET 4.5. 

Check out the blog article

Thanks John you saved me some time and hopefully will save others on the Guild some time as well.

If you have any tips, tricks or resources you would like shared with the Guild please email them to me at chrisw_88@hotmail.com and I will post them here.