diff --git a/location.py b/location.py
index 74822c9..55d391f 100644
--- a/location.py
+++ b/location.py
@@ -81,6 +81,7 @@ class Location(ModelSQL, ModelView):
         for location in cls.search([
                 ('parent', 'child_of', storage_location_ids),
                 ]):
-            if location.warehouse.id in found_warehouse_ids:
+            if (location.warehouse
+                    and location.warehouse.id in found_warehouse_ids):
                 warehouse_location_ids.append(location.id)
         return [('id', 'in', warehouse_location_ids)]