diff --git a/search/index.php b/search/index.php
index 3908025920b..205f3b482f4 100644
--- a/search/index.php
+++ b/search/index.php
@@ -48,9 +48,6 @@ if (!empty($CFG->forcelogin)) {
     require_login();
 }
 
-// Unlock the session during a search.
-\core\session\manager::write_close();
-
 require_capability('moodle/search:query', $context);
 
 $searchrenderer = $PAGE->get_renderer('core_search');
@@ -169,6 +166,9 @@ $PAGE->set_url($url);
 // We are ready to render.
 echo $OUTPUT->header();
 
+// Unlock the session only after outputting the header as this modifies the session cachestore.
+\core\session\manager::write_close();
+
 // Get the results.
 if ($data) {
     $results = $search->paged_search($data, $page);