Change MySQL Password on Zentyal

1.Change the default password in the config file for Zentyal

Code:
sudo nano /var/lib/ebox/conf/ebox-zarafa.passwd
2. Copy and paste the password to a text file for root login later. Comment out the password in the file and list your new password for mysql. Then press ctrl ‘x’ then ‘y’
3. Stop the MySQL Server.

Code:
sudo /etc/init.d/mysql stop
4. Start the mysqld configuration

Code:
sudo mysqld – – skip-grant-tables &
5. Login to MySQL as root. EDIT: Use original password in “ebox-zarafa.passwd”, the one you commented out in step 2

Code:
mysql -u root mysql
6. Replace YOURNEWPASSWORD with your new password!

Code:
UPDATE user SET Password=PASSWORD(‘YOURNEWPASSWORD’) WHERE
User=’root’; FLUSH PRIVILEGES; exit;

You can then install phpmyadmin and gain access for root

source : http://forum.zentyal.org/index.php?topic=4844.0