diff --git a/htdocs/core/class/conf.class.php b/htdocs/core/class/conf.class.php
index 0eeed26b0e2..60ee78bbff5 100644
--- a/htdocs/core/class/conf.class.php
+++ b/htdocs/core/class/conf.class.php
@@ -173,7 +173,7 @@ class Conf
 	{
 		dol_syslog(get_class($this)."::setValues");
 
-		if (!defined('NOREQUIREDB')) {
+		if (!is_null($db) && is_object($db)) {
 			// Define all global constants into $this->global->key=value
 			$sql = "SELECT ".$db->decrypt('name')." as name,";
 			$sql .= " ".$db->decrypt('value')." as value, entity";
diff --git a/htdocs/master.inc.php b/htdocs/master.inc.php
index a24b52859c4..e04adb4ee86 100644
--- a/htdocs/master.inc.php
+++ b/htdocs/master.inc.php
@@ -133,6 +133,7 @@ if (!defined('NOREQUIRETRAN')) {
 /*
  * Object $db
  */
+$db = null;
 if (!defined('NOREQUIREDB')) {
 	$db = getDoliDBInstance($conf->db->type, $conf->db->host, $conf->db->user, $conf->db->pass, $conf->db->name, $conf->db->port);