• In config_default_inc.php or config_inc.php

$g_session_save_path = '/tmp';

• In core/session_api.php

Index: session_api.php

--- session_api.php (revision 20)
+++ session_api.php (working copy)
@@ -49,6 +49,11 @@
*/
class MantisPHPSession extends MantisSession {
function __construct() {

• $t_session_save_path = session_save_path();
• if (empty($t_session_save_path))
• {
• session_save_path(config_get('session_save_path'));
• }
  session_start();
  $this->id = session_id();
  }