diff --git a/backup/backup.php b/backup/backup.php
index 688726daee3..4e8ba890acf 100644
--- a/backup/backup.php
+++ b/backup/backup.php
@@ -138,7 +138,9 @@ if ($backup->get_stage() == backup_ui::STAGE_FINAL) {
     }
 
     // Get HTML from logger.
-    $loghtml = $logger->get_html();
+    if ($CFG->debugdisplay) {
+        $loghtml = $logger->get_html();
+    }
 
     // Hide the progress display and first backup step bar (the 'finished' step will show next).
     echo html_writer::end_div();
diff --git a/backup/restore.php b/backup/restore.php
index 25a216cff0f..ab97369cb6c 100644
--- a/backup/restore.php
+++ b/backup/restore.php
@@ -110,7 +110,9 @@ if (!$restore->is_independent()) {
             // Do actual restore.
             $restore->execute();
             // Get HTML from logger.
-            $loghtml = $logger->get_html();
+            if ($CFG->debugdisplay) {
+                $loghtml = $logger->get_html();
+            }
             // Hide this section because we are now going to make the page show 'finished'.
             echo html_writer::end_div();
             echo html_writer::script('document.getElementById("executionprogress").style.display = "none";');