diff --git a/htdocs/holiday/common.inc.php b/htdocs/holiday/common.inc.php
index 93735fe0761..d321d6d386e 100644
--- a/htdocs/holiday/common.inc.php
+++ b/htdocs/holiday/common.inc.php
@@ -23,7 +23,7 @@
  *		\brief      Common load of data
  */
 
-require dirname(__FILE__).'/../main.inc.php';
+require_once realpath(dirname(__FILE__)) . '/../main.inc.php';
 if (! class_exists('Holiday')) {
 	require DOL_DOCUMENT_ROOT. '/holiday/class/holiday.class.php';
 }