Ticket #29891: 29891-01.patch

src/wp-admin/includes/ms.php

@@ -35 +35 @@
         if ( upload_is_user_over_quota( false ) ) {
                 $file['error'] = __( 'You have used your space quota. Please delete files before uploading.' );
         }
-        if ( $file['error'] != '0' && !isset($_POST['html-upload']) )
+        if ( $file['error'] != '0' && ! isset( $_POST['html-upload'] ) && ( ! defined( 'DOING_AJAX' ) || DOING_AJAX != true ) ) {
                 wp_die( $file['error'] . ' <a href="javascript:history.go(-1)">' . __( 'Back' ) . '</a>' );
+        }
 
         return $file;
 }