WordPress: Disable “Add New” on Custom Post Type

Solution for : WordPress: Disable “Add New” on Custom Post Type

There is a meta capability create_posts that is not documented but is used by WordPress to check before inserting the various 'Add New' buttons and links. In your custom post type declaration, add capabilities (not to be confused with cap) and then set it to false as below.

register_post_type( 'custom_post_type_name', array(
  'capability_type' => 'post',
  'capabilities' => array(
    'create_posts' => 'do_not_allow', // false < WP 4.5, credit @Ewout
  ),
  'map_meta_cap' => true, // Set to `false`, if users are not allowed to edit/delete existing posts
));