NTPd quits with following error:

Starting ntpd.
su: unknown login: ntpd
/etc/rc.d/ntpd: WARNING: failed to start ntpd

Just enter following commands to rebuild master password database and remove old ntpd.pid file:

# /usr/sbin/pwd_mkdb -p /etc/master.passw
# pkill ntpd
# rm /var/db/ntp/ntpd.pid
# service ntpd start