diff --git a/sale.py b/sale.py
index b6f9fe8..714209c 100644
--- a/sale.py
+++ b/sale.py
@@ -38,7 +38,7 @@ class Sale(metaclass=PoolMeta):
         for sales, values in zip(actions, actions):
             if 'origin' in values:
                 for sale in sales:
-                    if isinstance(crm.origin, Opportunity):
+                    if sale.origin and isinstance(sale.origin, Opportunity):
                         raise AccessError(gettext(
                                 'sale_opportunity'
                                 '.msg_modify_origin_opportunity',