diff --git a/addons/account/models/res_config_settings.py b/addons/account/models/res_config_settings.py
index 6949c38ea6c..40c898cfd83 100644
--- a/addons/account/models/res_config_settings.py
+++ b/addons/account/models/res_config_settings.py
@@ -1,6 +1,8 @@
 # -*- coding: utf-8 -*-
 # Part of Odoo. See LICENSE file for full copyright and licensing details.
 
+from ast import literal_eval
+
 from odoo import api, fields, models, _
 
 
@@ -64,9 +66,16 @@ class ResConfigSettings(models.TransientModel):
     def get_values(self):
         res = super(ResConfigSettings, self).get_values()
         params = self.env['ir.config_parameter'].sudo()
+        tax = self.env['account.tax'].sudo()
+        default_purchase_tax_id = literal_eval(params.get_param('account.default_purchase_tax_id', default='False'))
+        default_sale_tax_id = literal_eval(params.get_param('account.default_sale_tax_id', default='False'))
+        if default_purchase_tax_id and not tax.browse(default_purchase_tax_id).exists():
+            default_purchase_tax_id = False
+        if default_sale_tax_id and not tax.browse(default_sale_tax_id).exists():
+            default_sale_tax_id = False
         res.update(
-            default_purchase_tax_id=int(params.get_param('account.default_purchase_tax_id', default=False)) or False,
-            default_sale_tax_id=int(params.get_param('account.default_sale_tax_id', default=False)) or False
+            default_purchase_tax_id=default_purchase_tax_id,
+            default_sale_tax_id=default_sale_tax_id,
         )
         return res
 
diff --git a/addons/auth_signup/models/res_config_settings.py b/addons/auth_signup/models/res_config_settings.py
index 93436c80fab..7350121137b 100644
--- a/addons/auth_signup/models/res_config_settings.py
+++ b/addons/auth_signup/models/res_config_settings.py
@@ -20,11 +20,14 @@ class ResConfigSettings(models.TransientModel):
     def get_values(self):
         res = super(ResConfigSettings, self).get_values()
         get_param = self.env['ir.config_parameter'].sudo().get_param
+        auth_signup_template_user_id = literal_eval(get_param('auth_signup.template_user_id', default='False'))
+        if auth_signup_template_user_id and not self.env['res.users'].sudo().browse(auth_signup_template_user_id).exists():
+            auth_signup_template_user_id = False
         # the value of the parameter is a nonempty string
         res.update(
             auth_signup_reset_password=get_param('auth_signup.reset_password', 'False').lower() == 'true',
             auth_signup_uninvited='b2c' if get_param('auth_signup.allow_uninvited', 'False').lower() == 'true' else 'b2b',
-            auth_signup_template_user_id=literal_eval(get_param('auth_signup.template_user_id', 'False')),
+            auth_signup_template_user_id=auth_signup_template_user_id,
         )
         return res
 
diff --git a/addons/sale/models/res_config_settings.py b/addons/sale/models/res_config_settings.py
index 441d8eefb5d..f9016c90143 100644
--- a/addons/sale/models/res_config_settings.py
+++ b/addons/sale/models/res_config_settings.py
@@ -1,6 +1,8 @@
 # -*- coding: utf-8 -*-
 # Part of Odoo. See LICENSE file for full copyright and licensing details.
 
+from ast import literal_eval
+
 from odoo import api, fields, models
 
 
@@ -136,11 +138,14 @@ class ResConfigSettings(models.TransientModel):
         ICPSudo = self.env['ir.config_parameter'].sudo()
         sale_pricelist_setting = ICPSudo.get_param('sale.sale_pricelist_setting')
         sale_portal_confirmation_options = ICPSudo.get_param('sale.sale_portal_confirmation_options', default='none')
+        default_deposit_product_id = literal_eval(ICPSudo.get_param('sale.default_deposit_product_id', default='False'))
+        if default_deposit_product_id and not self.env['product.product'].browse(default_deposit_product_id).exists():
+            default_deposit_product_id = False
         res.update(
             auth_signup_uninvited='b2c' if ICPSudo.get_param('auth_signup.allow_uninvited', 'False').lower() == 'true' else 'b2b',
             use_sale_note=ICPSudo.get_param('sale.use_sale_note', default=False),
             auto_done_setting=ICPSudo.get_param('sale.auto_done_setting'),
-            default_deposit_product_id=int(ICPSudo.get_param('sale.default_deposit_product_id')),
+            default_deposit_product_id=default_deposit_product_id,
             sale_show_tax=ICPSudo.get_param('sale.sale_show_tax', default='subtotal'),
             multi_sales_price=sale_pricelist_setting in ['percentage', 'formula'],
             multi_sales_price_method=sale_pricelist_setting in ['percentage', 'formula'] and sale_pricelist_setting or False,
diff --git a/addons/website_sale/models/res_config_settings.py b/addons/website_sale/models/res_config_settings.py
index c83d92b2b19..74ad507499d 100644
--- a/addons/website_sale/models/res_config_settings.py
+++ b/addons/website_sale/models/res_config_settings.py
@@ -1,6 +1,8 @@
 # -*- coding: utf-8 -*-
 # Part of Odoo. See LICENSE file for full copyright and licensing details.
 
+from ast import literal_eval
+
 from odoo import api, models, fields
 
 class ResConfigSettings(models.TransientModel):
@@ -62,8 +64,8 @@ class ResConfigSettings(models.TransientModel):
             if self.env['ir.module.module'].search([('name', '=', 'website_sale_delivery')], limit=1).state in ('installed', 'to install', 'to upgrade'):
                 sale_delivery_settings = 'website'
 
-        cart_recovery_mail_template = int(params.get_param('website_sale.cart_recovery_mail_template_id'))
-        if not cart_recovery_mail_template:
+        cart_recovery_mail_template = literal_eval(params.get_param('website_sale.cart_recovery_mail_template_id', default='False'))
+        if cart_recovery_mail_template and not self.env['mail.template'].browse(cart_recovery_mail_template).exists():
             cart_recovery_mail_template = self._default_recovery_mail_template()
 
         res.update(