diff --git a/addons/mrp_subcontracting/i18n/mrp_subcontracting.pot b/addons/mrp_subcontracting/i18n/mrp_subcontracting.pot
index 47fada171ff..31bea2e6a94 100644
--- a/addons/mrp_subcontracting/i18n/mrp_subcontracting.pot
+++ b/addons/mrp_subcontracting/i18n/mrp_subcontracting.pot
@@ -361,6 +361,12 @@ msgid ""
 "subcontracting."
 msgstr ""
 
+#. module: mrp_subcontracting
+#: code:addons/mrp_subcontracting/models/mrp_production.py:0
+#, python-format
+msgid "You must enter a serial number for %s"
+msgstr ""
+
 #. module: mrp_subcontracting
 #: code:addons/mrp_subcontracting/models/mrp_production.py:0
 #, python-format
diff --git a/addons/mrp_subcontracting/models/mrp_production.py b/addons/mrp_subcontracting/models/mrp_production.py
index 599861d34f4..b5bef8c1366 100644
--- a/addons/mrp_subcontracting/models/mrp_production.py
+++ b/addons/mrp_subcontracting/models/mrp_production.py
@@ -41,6 +41,8 @@ class MrpProduction(models.Model):
             raise UserError(_("This MO isn't related to a subcontracted move"))
         if float_is_zero(self.qty_producing, precision_rounding=self.product_uom_id.rounding):
             return {'type': 'ir.actions.act_window_close'}
+        if self.product_tracking != 'none' and not self.lot_producing_id:
+            raise UserError(_('You must enter a serial number for %s') % self.product_id.name)
         for sml in self.move_raw_ids.move_line_ids:
             if sml.tracking != 'none' and not sml.lot_id:
                 raise UserError(_('You must enter a serial number for each line of %s') % sml.product_id.name)
@@ -67,6 +69,11 @@ class MrpProduction(models.Model):
             return action
         return {'type': 'ir.actions.act_window_close'}
 
+    def action_subcontracting_discard_remaining_components(self):
+        self.ensure_one()
+        self.qty_producing = 0
+        return {'type': 'ir.actions.act_window_close'}
+
     def _pre_button_mark_done(self):
         if self._get_subcontract_move():
             return True
@@ -141,7 +148,7 @@ class MrpProduction(models.Model):
                 return False
             if not all(line.lot_id for line in mo.move_raw_ids.filtered(lambda sm: sm.has_tracking != 'none').move_line_ids):
                 return False
-            if mo.product_id.tracking != 'none' and not mo.lot_producing_id:
+            if mo.product_tracking != 'none' and not mo.lot_producing_id:
                 return False
             return True
 
diff --git a/addons/mrp_subcontracting/views/mrp_production_views.xml b/addons/mrp_subcontracting/views/mrp_production_views.xml
index 1107d551539..783007ebae0 100644
--- a/addons/mrp_subcontracting/views/mrp_production_views.xml
+++ b/addons/mrp_subcontracting/views/mrp_production_views.xml
@@ -19,7 +19,7 @@
                 <attribute name="invisible">1</attribute>
             </xpath>
             <xpath expr="//field[@name='lot_producing_id']" position="attributes">
-                <attribute name="attrs">{'invisible': [('product_tracking', 'in', ('none', False))], 'required': [('product_tracking', 'not in', ('none', False))]}</attribute>
+                <attribute name="attrs">{'invisible': [('product_tracking', 'in', ('none', False))]}</attribute>
             </xpath>
             <xpath expr="//page[@name='miscellaneous']" position="attributes">
                 <attribute name="invisible">1</attribute>
@@ -46,7 +46,7 @@
                 <footer>
                     <button name="subcontracting_record_component" attrs="{'invisible': ['|', ('state', '=', 'to_close'), ('qty_producing', '&lt;', 0.001)]}" string="Continue" type="object" class="oe_highlight" data-hotkey="q"/>
                     <button name="subcontracting_record_component" attrs="{'invisible': [('state', '!=', 'to_close')]}" string="Record Production" type="object" class="oe_highlight" data-hotkey="q"/>
-                    <button string="Discard" special="cancel" data-hotkey="z" />
+                    <button name="action_subcontracting_discard_remaining_components" string="Discard" type="object" data-hotkey="z"/>
                 </footer>
             </xpath>
         </field>