diff --git a/phpBB/includes/session.php b/phpBB/includes/session.php
index 54f0167ab2..b03bc16588 100644
--- a/phpBB/includes/session.php
+++ b/phpBB/includes/session.php
@@ -1508,7 +1508,7 @@ class user extends session
 		}
 		
 		// Make sure the user is able to hide his session
-		if (!$this->data['session_viewonline'])
+		if (if isset($this->data['session_viewonline']) && !$this->data['session_viewonline'])
 		{
 			// Reset online status if not allowed to hide the session...
 			if (!$auth->acl_get('u_hideonline'))