Login as admin. Create user (u1). Logout. Login as u1. Edit the profile and upload a picture. Logout. Login as admin. Access to "Site administration / Users / Accounts / Browse list of users" and remove user u1. Execute SQL and annotate the result (in empty installations, it should be 1):  SELECT count(p.*) FROM mdl_files p LEFT JOIN mdl_files o ON (p.filename = o.contenthash) WHERE p.component = 'core' AND (p.filearea = 'preview' OR p.filearea = 'documentconversion') AND p.itemid = 0 AND o.id IS NULL Run the cleanup task:  php admin/tool/task/cli/schedule_task.php --execute='\core\task\file_trash_cleanup_task' Execute again SQL and annotate the result:  SELECT count(p.*) FROM mdl_files p LEFT JOIN mdl_files o ON (p.filename = o.contenthash) WHERE p.component = 'core' AND (p.filearea = 'preview' OR p.filearea = 'documentconversion') AND p.itemid = 0 AND o.id IS NULL Check the result now is lower than number in #9 (in empty installations, it should be 0).