diff --git a/product_category_default_ecommerce_cat/models/product_product.py b/product_category_default_ecommerce_cat/models/product_product.py
index 3f1f985..935b418 100644
--- a/product_category_default_ecommerce_cat/models/product_product.py
+++ b/product_category_default_ecommerce_cat/models/product_product.py
@@ -16,7 +16,8 @@ class ProductProduct(models.Model):
             #check if there are public categories setup by user
             new_cats = []
             old_cats = vals.get("public_categ_ids")
-            if old_cats[0][2]:
+            if old_cats:
+              if old_cats[0][2]:
                 for i in old_cats[0][2]:
                     new_cats.append(i)
             category = self.env['product.category'].browse(categ_id)