diff --git a/addons/mrp/models/mrp_production.py b/addons/mrp/models/mrp_production.py
index 16325a98500..5e3bb3a91bf 100644
--- a/addons/mrp/models/mrp_production.py
+++ b/addons/mrp/models/mrp_production.py
@@ -349,7 +349,7 @@ class MrpProduction(models.Model):
             source_location = routing.location_id
         else:
             source_location = self.location_src_id
-        original_quantity = self.product_qty - self.qty_produced
+        original_quantity = (self.product_qty - self.qty_produced) or 1.0
         data = {
             'sequence': bom_line.sequence,
             'name': self.name,