diff --git a/interface/lib/classes/tools_monitor.inc.php b/interface/lib/classes/tools_monitor.inc.php
index d57b9b7a3f425a291c842ef089183aea1f59a3f4..91040174683f42e4f27530ff31cfc9270a45c991 100644
--- a/interface/lib/classes/tools_monitor.inc.php
+++ b/interface/lib/classes/tools_monitor.inc.php
@@ -568,7 +568,7 @@ class tools_monitor {
 
 		if(isset($record['data'])) {
 			$data = unserialize($record['data']);
-			$html = nl2br($data['output']);
+                       $html = '<pre>' . htmlspecialchars($data['output']) . '</pre>';
 		} else {
 			$html = '<p>'.$app->lng("no_data_mailq_txt").'</p>';
 		}