diff --git a/admin/tool/task/run_adhoctasks.php b/admin/tool/task/run_adhoctasks.php
index 1b45035d8938c..0e123677915f6 100644
--- a/admin/tool/task/run_adhoctasks.php
+++ b/admin/tool/task/run_adhoctasks.php
@@ -111,7 +111,7 @@ function ($t) use ($now) {
 \core\session\manager::write_close();
 
 // Prepare to handle output via mtrace.
-require('lib.php');
+require_once("{$CFG->dirroot}/{$CFG->admin}/tool/task/lib.php");
 $CFG->mtrace_wrapper = 'tool_task_mtrace_wrapper';
 
 // Run the specified tasks.
diff --git a/admin/tool/task/schedule_task.php b/admin/tool/task/schedule_task.php
index c7753f5425a92..95acc4b08e003 100644
--- a/admin/tool/task/schedule_task.php
+++ b/admin/tool/task/schedule_task.php
@@ -85,7 +85,8 @@
 
 // Prepare to handle output via mtrace.
 echo html_writer::start_tag('pre');
-require('lib.php');
+
+require_once("{$CFG->dirroot}/{$CFG->admin}/tool/task/lib.php");
 $CFG->mtrace_wrapper = 'tool_task_mtrace_wrapper';
 
 // Run the specified task (this will output an error if it doesn't exist).