systemd-timesyncd.service start fails

Solution 1:

The exclamation mark negates the condition; in other words the condition that fails says: "enable if an executable file /usr/sbin/ntpd does not exist". This fails for you because /usr/bin/ntpd does exist and is executable.

The logic behind this line is that systemd-timesyncd should only be enabled if ntpd is not installed; otherwise it would be redundant (at best) or interfere with ntpd (at worst). Since you or your distribution installed ntpd, timesyncd's service file makes it back off and let ntpd be your NTP client.

If you want to tun systemd-timesyncd, you should remove ntpd. If you only want to try it out for testing, you could override the line in the service file by creating a file called /etc/systemd/system/systemd-timesyncd.service with the contents:

ConditionFileIsExecutable=