diff --git a/lib/weblib.php b/lib/weblib.php
index e8e2e95de39..31d2a1365e6 100644
--- a/lib/weblib.php
+++ b/lib/weblib.php
@@ -3253,8 +3253,7 @@ class text_progress_trace extends progress_trace {
      * @return void Output is echo'd
      */
     public function output($message, $depth = 0) {
-        echo str_repeat('  ', $depth), $message, "\n";
-        flush();
+        mtrace(str_repeat('  ', $depth) . $message);
     }
 }