Jacob Santos has posted an extensive tutorial describing “WordPress 2.7 Plugin Uninstall functionality and how to use it to make the uninstall process easy and seamless.” Jacob adds that the “uninstall” hook runs when the user deletes a plugin that is deactivated. There are two ways to register the uninstaller with WordPress.

1. Create uninstall.php at the base of your plugin folder.
2. Register your plugin's uninstall hook.

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