The Microsoft documentation states that ActiveDirectoryMembershipUser will throw a NotSupportedException when any attempt is made to access properties LastLoginDate and LastActivityDate. See http://msdn2.microsoft.com/en-us/library/system.web.security.activedirectorymembershipuser.lastlogindate.aspx and http://msdn2.microsoft.com/en-us/library/system.web.security.activedirectorymembershipuser.lastactivitydate.aspx In consequence attempting to do EditUser in admin mode on an account returned by the ActiveDirectoryMembershipProvider causes:- The property 'LastLoginDate' is not supported by the Active Directory membership provider. Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. Exception Details: System.NotSupportedException: The property 'LastLoginDate' is not supported by the Active Directory membership provider. Source Error: An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below. Stack Trace: [NotSupportedException: The property 'LastLoginDate' is not supported by the Active Directory membership provider.] System.Web.Security.ActiveDirectoryMembershipUser.get_LastLoginDate() +107 EPiServer.UI.Edit.UserMembership.PopulateMembershipFields() +341 EPiServer.UI.Edit.UserMembership.OnLoad(EventArgs e) +881 System.Web.UI.Control.LoadRecursive() +47 System.Web.UI.Control.LoadRecursive() +131 System.Web.UI.Control.LoadRecursive() +131 System.Web.UI.Control.LoadRecursive() +131 System.Web.UI.Control.LoadRecursive() +131 System.Web.UI.Control.LoadRecursive() +131 System.Web.UI.Control.LoadRecursive() +131 System.Web.UI.Control.LoadRecursive() +131 System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +1061