diff --git a/op/op.Login.php b/op/op.Login.php
index 541ccb936..e9763ff97 100644
--- a/op/op.Login.php
+++ b/op/op.Login.php
@@ -89,6 +89,7 @@ $controller->setParam('sesstheme', $sesstheme);
 $controller->setParam('referuri', $referuri);
 $controller->setParam('session', $session);
 if(!$controller->run()) {
+	$session = null;
 	add_log_line("login failed", PEAR_LOG_ERR);
 	_printMessage(getMLText($controller->getErrorMsg()), getMLText($controller->getErrorMsg())."\n");
 	exit;