Stop all outgoing emails sent from WordPress.
The emails are lost forever.
Most likely, this is due to a plugin you have running. There are two different things the plugin could be doing to cause emails to still be sent.
Unfortunately in either of these cases, this plugin will not be able to stop the email.
You can enable logging of stopped emails on the admin menu page Settings > Stop Emails.
Emails will be logged to your PHP error log.
Activating a plugin normally requires logging into the site. Installing the file in the mu-plugins directory allows you to activate the plugin without logging in. This can be helpful when setting up an existing site locally.
Please report bugs at https://github.com/salcode/stop-emails/issues