diff --git a/addons/stock/models/stock_move_line.py b/addons/stock/models/stock_move_line.py
index 1423392113c..1b3a68ec083 100644
--- a/addons/stock/models/stock_move_line.py
+++ b/addons/stock/models/stock_move_line.py
@@ -249,7 +249,7 @@ class StockMoveLine(models.Model):
         precision = self.env['decimal.precision'].precision_get('Product Unit of Measure')
         for ml in self:
             if ml.state in ('done', 'cancel'):
-                raise UserError(_('You can not delete pack operations of a done picking'))
+                raise UserError(_('You can not delete product moves if the picking is done. You can only correct the done quantities.'))
             # Unlinking a move line should unreserve.
             if ml.product_id.type == 'product' and not ml.location_id.should_bypass_reservation() and not float_is_zero(ml.product_qty, precision_digits=precision):
                 self.env['stock.quant']._update_reserved_quantity(ml.product_id, ml.location_id, -ml.product_qty, lot_id=ml.lot_id,