diff --git a/addons/sale_timesheet/models/sale_order.py b/addons/sale_timesheet/models/sale_order.py
index 533b8ff42aa..9a09d2648e7 100644
--- a/addons/sale_timesheet/models/sale_order.py
+++ b/addons/sale_timesheet/models/sale_order.py
@@ -56,6 +56,7 @@ class SaleOrder(models.Model):
         upsellable_orders = self.filtered(lambda so:
             so.state == 'sale'
             and so.invoice_status != 'upselling'
+            and so.id
             and (so.user_id or so.partner_id.user_id)  # salesperson needed to assign upsell activity
         )
         for order in upsellable_orders: