Ticket #16928: 16928.diff

wp-includes/js/autosave.dev.js

@@ -86 +86 @@
         var res = wpAjax.parseAjaxResponse(response, 'autosave'), message = '', postID, sup, url;
 
         if ( res && res.responses && res.responses.length ) {
-                message = res.responses[0].data; // The saved message or error.
+                message = res.responses[0].data || ( res.responses[0].errors.length && res.responses[0].errors[0].message ); // The saved message or error.             
                 // someone else is editing: disable autosave, set errors
                 if ( res.responses[0].supplemental ) {
                         sup = res.responses[0].supplemental;