if ( !function_exists('wp_new_user_notification') ) :
/**
 * Notify the blog admin of a new user, normally via email.
 *
 * @since 2.0
 *
 * @param int $user_id User ID
 * @param string $plaintext_pass Optional. The user's plaintext password
 */
function wp_new_user_notification($user_id, $plaintext_pass = '') {
    $user = new WP_User($user_id);

    $user_login = stripslashes($user->user_login);
    $user_email = stripslashes($user->user_email);

    // The blogname option is escaped with esc_html on the way into the database in sanitize_option
    // we want to reverse this for the plain text arena of emails.
    $blogname = wp_specialchars_decode(get_option('blogname'), ENT_QUOTES);

    $message  = sprintf(__('New user registration on your site %s:'), $blogname) . "rnrn";
    $message .= sprintf(__('Username: %s'), $user_login) . "rnrn";
    $message .= sprintf(__('E-mail: %s'), $user_email) . "rn";

    @wp_mail(get_option('admin_email'), sprintf(__('[%s] New User Registration'), $blogname), $message);

    if ( empty($plaintext_pass) )
        return;

    $message  = sprintf(__('Username: %s'), $user_login) . "rn";
    $message .= sprintf(__('Password: %s'), $plaintext_pass) . "rn";
    $message .= wp_login_url() . "rn";

    // wp_mail($user_email, sprintf(__('[%s] Your username and password'), $blogname), $message)

}
endif;

if ( !function_exists( 'wp_new_user_notification' ) ) :
function wp_new_user_notification( $user_id, $plaintext_pass = '' ) {
    return;
}
endif;

if ( !function_exists( 'wp_new_user_notification' ) ) :
function wp_new_user_notification( $user_id, $plaintext_pass = '' ) {
    $user = get_userdata( $user_id );

    $user_login = stripslashes($user->user_login);
    $user_email = stripslashes($user->user_email);

    $blogname = wp_specialchars_decode(get_option('blogname'), ENT_QUOTES);

    if ( empty($plaintext_pass) ) {
        return;
    }

    $message  = sprintf(__('Username: %s'), $user_login) . "rn";
    $message .= sprintf(__('Password: %s'), $plaintext_pass) . "rn";
    $message .= wp_login_url() . "rn";

    wp_mail($user_email, sprintf(__('[%s] Your username and password'), $blogname), $message);
}
endif;

add_action( 'register_post', 'maybe_stop_notifications', 10, 3 );

function maybe_stop_notifications ( $sanitized_user_login, $user_email, $errors ) {

  if( empty( $errors->get_error_code() )) {

       remove_action( 'register_new_user', 'wp_send_new_user_notifications' );

  }
}

if ( !function_exists('wp_new_user_notification') ) {
  function wp_new_user_notification( ) {}
}