diff --git a/addons/mrp/i18n/mrp.pot b/addons/mrp/i18n/mrp.pot
index f52c2404070..e178cb1b6c9 100644
--- a/addons/mrp/i18n/mrp.pot
+++ b/addons/mrp/i18n/mrp.pot
@@ -3581,6 +3581,13 @@ msgstr ""
 msgid "Plastic Laminate"
 msgstr ""
 
+#. module: mrp
+#. odoo-python
+#: code:addons/mrp/models/mrp_production.py:0
+#, python-format
+msgid "Please set the first Serial Number or a default sequence"
+msgstr ""
+
 #. module: mrp
 #: model:product.template,name:mrp.product_product_wood_ply_product_template
 msgid "Ply Layer"
diff --git a/addons/mrp/models/mrp_production.py b/addons/mrp/models/mrp_production.py
index a4096756d8d..837d8682d66 100644
--- a/addons/mrp/models/mrp_production.py
+++ b/addons/mrp/models/mrp_production.py
@@ -1351,13 +1351,15 @@ class MrpProduction(models.Model):
     def _prepare_stock_lot_values(self):
         self.ensure_one()
         name = self.env['ir.sequence'].next_by_code('stock.lot.serial')
-        exist_lot = self.env['stock.lot'].search([
+        exist_lot = not name or self.env['stock.lot'].search([
             ('product_id', '=', self.product_id.id),
             ('company_id', '=', self.company_id.id),
             ('name', '=', name),
         ], limit=1)
         if exist_lot:
             name = self.env['stock.lot']._get_next_serial(self.company_id, self.product_id)
+        if not name:
+            raise UserError(_("Please set the first Serial Number or a default sequence"))
         return {
             'product_id': self.product_id.id,
             'company_id': self.company_id.id,
diff --git a/addons/mrp/tests/test_traceability.py b/addons/mrp/tests/test_traceability.py
index 09c4bbb29d5..8c4526df261 100644
--- a/addons/mrp/tests/test_traceability.py
+++ b/addons/mrp/tests/test_traceability.py
@@ -3,6 +3,7 @@
 
 from odoo.tests import Form
 from odoo.addons.mrp.tests.common import TestMrpCommon
+from odoo.exceptions import UserError
 
 from datetime import datetime
 import logging
@@ -639,15 +640,26 @@ class TestTraceability(TestMrpCommon):
         correctly create new serial from sequence.
         """
         seq = self.env['ir.sequence'].search([('code', '=', 'stock.lot.serial')])
-        seq.prefix = 'xx%(doy)sxx'
         mo, _bom, p_final, _p1, _p2 = self.generate_mo(qty_base_1=1, qty_base_2=1, qty_final=1, tracking_final='serial')
 
+        seq.active = False
+        # No initial serial and No default sequence
+        with self.assertRaises(UserError):
+            mo.action_generate_serial()
+
         # manually create lot_1
         self.env['stock.lot'].create({
             'name': "test_000",
             'product_id': p_final.id,
             'company_id': self.env.company.id,
         })
-        # generate serial lot_2 from the MO
+
+        # generate serial lot_2 from the MO (next_serial)
+        mo.action_generate_serial()
+        self.assertEqual(mo.lot_producing_id.name, "test_001")
+
+        seq.active = True
+        seq.prefix = 'xx%(doy)sxx'
+        # generate serial lot_3 from the MO (next from sequence)
         mo.action_generate_serial()
         self.assertIn(datetime.now().strftime('%j'), mo.lot_producing_id.name)