diff --git a/classes/stock/Warehouse.php b/classes/stock/Warehouse.php
index 18c745529..244f1283d 100644
--- a/classes/stock/Warehouse.php
+++ b/classes/stock/Warehouse.php
@@ -164,6 +164,9 @@ class WarehouseCore extends ObjectModel
 
 		$res = Db::getInstance(_PS_USE_SQL_SLAVE_)->executeS($query);
 
+		if (!is_array($res))
+			return $ids_carrier;
+
 		foreach ($res as $carriers)
 			foreach ($carriers as $carrier)
 				$ids_carrier[] = $carrier;
@@ -592,6 +595,9 @@ class WarehouseCore extends ObjectModel
 
 		$res = Db::getInstance(_PS_USE_SQL_SLAVE_)->executeS($query);
 
+		if (!is_array($res))
+			return $ids_carrier;
+
 		foreach ($res as $carriers)
 			foreach ($carriers as $carrier)
 				$ids_carrier[] = $carrier;