diff --git a/wp-includes/nav-menu.php b/wp-includes/nav-menu.php
index 7208d9bbf5..70a450e395 100644
--- a/wp-includes/nav-menu.php
+++ b/wp-includes/nav-menu.php
@@ -762,13 +762,15 @@ function wp_setup_nav_menu_item( $menu_item ) {
 				$object =  get_post_type_object( $menu_item->object );
 				if ( $object ) {
 					$menu_item->title = '' == $menu_item->post_title ? $object->labels->archives : $menu_item->post_title;
+					$post_type_description = $object->description;
 				} else {
 					$menu_item->_invalid = true;
+					$post_type_description = '';
 				}
 
 				$menu_item->type_label = __( 'Post Type Archive' );
 				$post_content = wp_trim_words( $menu_item->post_content, 200 );
-				$post_type_description = '' == $post_content ? $object->description : $post_content; 
+				$post_type_description = '' == $post_content ? $post_type_description : $post_content; 
 				$menu_item->url = get_post_type_archive_link( $menu_item->object );
 			} elseif ( 'taxonomy' == $menu_item->type ) {
 				$object = get_taxonomy( $menu_item->object );
diff --git a/wp-includes/version.php b/wp-includes/version.php
index 4b763169e6..70f8d78e31 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.5-beta2-36887';
+$wp_version = '4.5-beta2-36888';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.