Reset MySQL root password using ALTER USER statement after install on Mac

I recently installed MySQL and it seems I have to reset the password after install. It won't let me do anything else. Now I already reset the password the usual way: update user set password = password('XXX') where user = root; (BTW: took me ages to work out that MySQL for some bizarre reason has renamed the field 'password' to 'authentication_string'. I am quite upset about changes like that.) Unfortunately it seems I need to change the password a different way that is unknown to me. Maybe someone here has already come across that problem?