The User Manager should be backed by a special profile, not the guest one.

chrome/browser/ui/cocoa/profiles/user_manager_mac.mm

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/ui/cocoa/profiles/user_manager_mac.h"
 
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/profiles/profile_manager.h"
 #include "chrome/browser/ui/browser_dialogs.h"
 #include "content/public/browser/web_contents.h"
@@ skipping 128 matching lines @@
 
 // static
 void UserManagerMac::Show(const base::FilePath& profile_path_to_focus,
                           profiles::UserManagerTutorialMode tutorial_mode) {
   if (instance_) {
     // If there's a user manager window open already, just activate it.
     [instance_->window_controller_ show];
     return;
   }
 
-  // Create the guest profile, if necessary, and open the User Manager
-  // from the guest profile.
-  profiles::CreateGuestProfileForUserManager(
+  // Create the User Manager profile, if necessary, and open the User Manager
+  // when the profile is ready.
+  profiles::CreateUserManagerProfile(
       profile_path_to_focus,
       tutorial_mode,
-      base::Bind(&UserManagerMac::OnGuestProfileCreated));
+      base::Bind(&UserManagerMac::OnUserManagerProfileCreated));
 }
 
 // static
 void UserManagerMac::Hide() {
   if (instance_)
     [instance_->window_controller_ close];
 }
 
 // static
 bool UserManagerMac::IsShowing() {
   return instance_ ? [instance_->window_controller_ isVisible]: false;
 }
 
 // static
-void UserManagerMac::OnGuestProfileCreated(Profile* guest_profile,
-                                           const std::string& url) {
-  instance_ = new UserManagerMac(guest_profile);
+void UserManagerMac::OnUserManagerProfileCreated(Profile* profile,
+                                                 const std::string& url) {
+  instance_ = new UserManagerMac(profile);
   [instance_->window_controller_ showURL:GURL(url)];
 }
 
 void UserManagerMac::WindowWasClosed() {
   instance_ = NULL;
   delete this;
 }