1. Заходим в phpMyAdmin.

2. Открываем вкладку «SQL» вставляем команду в окно UPDATE user SET Password=PASSWORD('Ваш пароль')WHERE User='root' и жмем «ВПЕРЕД»

3. Идем по пути opt/lampp/phpmyadmin/config.inc.php меняем конфиг.

<?php
/* vim: set expandtab sw=4 ts=4 sts=4: */
/**
* phpMyAdmin sample configuration, you can use it as base for
* manual configuration. For easier setup you can use setup/
*
* All directives are explained in documentation in the doc/ folder
* or at <docs.phpmyadmin.net/>.
*
* @package PhpMyAdmin
*/

/**
* This is needed for cookie based authentication to encrypt password in
* cookie. Needs to be 32 chars long.
*/
$cfg['blowfish_secret'] = 'xampp(xampp — Заменяем на 25-ти значные символы)'; /* YOU SHOULD CHANGE THIS FOR A MORE SECURE COOKIE AUTH! */

/**
* Servers configuration
*/
$i = 0;

/**
* First server
*/
$i++;
/* Authentication type */
$cfg['Servers'][$i]['auth_type'] = 'config (config — заменяем на cookie)';
$cfg['Servers'][$i]['user'] = 'root';
$cfg['Servers'][$i]['password'] = 'Ваш пароль';
/* Server parameters */
//$cfg['Servers'][$i]['host'] = 'localhost';
$cfg['Servers'][$i]['compress'] = false;
$cfg['Servers'][$i]['AllowNoPassword'] = true (true — заменяем на false);

4. Перезапускаем XAMPP.