This tutorial is going to show you how to disable automatic emails in Odoo without programming. The example shown is basing on Odoo 9 but it is likely to work on Odoo 10 and Odoo 8 as well. There are many different methods on how to achieve it, including module development. However, this tutorial is focusing on a simple solution.
1. Activate the developer mode and open settings
If you are using Odoo 10 or later you have to activate the developer mode in the settings. If you still don't know how to do it follow the tutorial on how to activate developer mode in Odoo
2. Navigate to Technical/Email/Subtypes
The list of messages will be displayed. Navigate to the one you want to change. You can recognise the working ones by checking if the "Default" column is checked.
3. Apply changes to chosen Subtype and save
For example, if the box "Default" was checked users would get an email as soon as the Sales Order is Confirmed.
If you hover over the fields appropriate hints will be displayed.
How to disable automatic email in Odoo?
Learn how to do it using subtypes
Odoo Odoo Technical Tutorial