diff --git a/modules/sale_opportunity/sale.py b/modules/sale_opportunity/sale.py
index a5d4b98d29..8a260b5296 100644
--- a/modules/sale_opportunity/sale.py
+++ b/modules/sale_opportunity/sale.py
@@ -38,7 +38,7 @@ class Sale(metaclass=PoolMeta):
         for sales, values in zip(actions, actions):
             if 'origin' in values:
                 origin = values['origin']
-                if not isinstance(origin, str):
+                if origin and not isinstance(origin, str):
                     origin = '%s,%s' % tuple(origin)
                 for sale in sales:
                     if (isinstance(sale.origin, Opportunity)