Ensure the old membership provider's count online members is implemented

src/Umbraco.Web/umbraco.presentation/umbraco/create/userTasks.cs

@@ -54,11 +54,15 @@ namespace umbraco
                 }
                 var login = parts[0];
                 var email = parts[1];
-                
 
                 var u = Membership.Providers[UmbracoSettings.DefaultBackofficeProvider].CreateUser(
                     login, password, email.Trim().ToLower(), "", "", true, null, out status);
 
+                if (u == null)
+                {
+                    return false;
+                }
+
                 _returnUrl = string.Format("users/EditUser.aspx?id={0}", u.ProviderUserKey.ToString());
 
                 return status == MembershipCreateStatus.Success;

src/umbraco.providers/members/UmbracoMembershipProvider.cs

@@ -10,6 +10,7 @@ using Umbraco.Core.Logging;
 using Umbraco.Core.Models;
 using Umbraco.Core.Persistence.Querying;
 using Umbraco.Core.Security;
+using Umbraco.Core.Services;
 using umbraco.BusinessLogic;
 using System.Security.Cryptography;
 using System.Web.Util;
@@ -405,7 +406,7 @@ namespace umbraco.providers.members
         /// </returns>
         public override int GetNumberOfUsersOnline()
         {
-            return Member.CachedMembers().Count;
+            return ApplicationContext.Current.Services.MemberService.GetMemberCount(MemberCountType.Online);
         }
 
         /// <summary>