Index: wp-includes/nav-menu-template.php
===================================================================
--- wp-includes/nav-menu-template.php	(revision 21499)
+++ wp-includes/nav-menu-template.php	(working copy)
@@ -171,8 +171,8 @@
 		&& $args->fallback_cb && is_callable( $args->fallback_cb ) )
 			return call_user_func( $args->fallback_cb, (array) $args );
 
-	// If no fallback function was specified and the menu doesn't exists, bail.
-	if ( !$menu || is_wp_error($menu) )
+	// If no fallback function was specified and the menu doesn't exist or has no items, bail.
+	if ( !$menu || is_wp_error( $menu ) || empty( $menu_items ) )
 		return false;
 
 	$nav_menu = $items = '';