diff --git a/wp-admin/admin-functions.php b/wp-admin/admin-functions.php
index 64e758a75f..52896892b8 100644
--- a/wp-admin/admin-functions.php
+++ b/wp-admin/admin-functions.php
@@ -2084,7 +2084,7 @@ function wp_check_for_changed_slugs($post_id) {
 	if ( $post->post_name == $_POST['wp-old-slug'] )
 		return $post_id;
 
-	$old_slugs = get_post_meta($post_id, '_wp_old_slug');
+	$old_slugs = (array) get_post_meta($post_id, '_wp_old_slug');
 
 	// if we haven't added this old slug before, add it now
 	if ( !count($old_slugs) || !in_array($_POST['wp-old-slug'], $old_slugs) )