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

After installing Visual Studio 2012 and .NET Framework 4.5 an error occurs when logging in in Sitecore (Version 6.4):

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

To fix this, change this setting in the web.config file from true to false:

<setting name="Login.RememberLastLoggedInUserName" value="false" />



This fix is from the comments section of this blog post: http://kamranicus.com/Blog/Posts/45/sitecore-and-net-framework-45

also: http://truncatedcodr.wordpress.com/2012/06/20/fix-sitecore-and-net-framework-4-5/