diff --git a/htdocs/lib/functions.lib.php b/htdocs/lib/functions.lib.php
index 74223873f45..7c31ca163bf 100644
--- a/htdocs/lib/functions.lib.php
+++ b/htdocs/lib/functions.lib.php
@@ -1902,7 +1902,7 @@ function dol_print_error($db='',$error='')
 		$out.="<b>".$langs->trans("Server").":</b> ".$_SERVER["SERVER_SOFTWARE"]."<br>\n";;
         $out.="<br>\n";
 		$out.="<b>".$langs->trans("RequestedUrl").":</b> ".$_SERVER["REQUEST_URI"]."<br>\n";;
-        $out.="<b>".$langs->trans("Referer").":</b> ".$_SERVER["HTTP_REFERER"]."<br>\n";;
+        $out.="<b>".$langs->trans("Referer").":</b> ".(isset($_SERVER["HTTP_REFERER"])?$_SERVER["HTTP_REFERER"]:'')."<br>\n";;
 		$out.="<b>".$langs->trans("MenuManager").":</b> ".$conf->top_menu.($conf->top_menu||$conf->left_menu?'/':'').$conf->left_menu."<br>\n";
 		$out.="<br>\n";
 		$syslog.="url=".$_SERVER["REQUEST_URI"];