Index: includes/menu.inc
===================================================================
--- includes/menu.inc	(revision 13)
+++ includes/menu.inc	(working copy)
@@ -2514,6 +2514,7 @@
     $query->condition('ml.mlid', $mlid);
     if ($item = $query->execute()->fetchAssoc()) {
       $item['weight'] = $item['link_weight'];
+      $item['enabled'] = true;
       _menu_link_translate($item);
       return $item;
     }
Index: modules/menu/menu.module
===================================================================
--- modules/menu/menu.module	(revision 13)
+++ modules/menu/menu.module	(working copy)
@@ -627,7 +627,7 @@
   $form['menu']['enabled'] = array(
     '#type' => 'checkbox',
     '#title' => t('Provide a menu link'),
-    '#default_value' => (int) (bool) $link['mlid'],
+    '#default_value' => (bool) $link['enabled'],
   );
   $form['menu']['link'] = array(
     '#type' => 'container',