[chrony-users] chronyd on High Sierra

[Bryan Christianson]

There is a bug in High Sierra (macOS 10.13) that leaves Apple's timed daemon active after it has been disabled in the System Settings 'Date and Time' preferences

timed continues to send NTP packets to the server specified in the System Preferences and then adjusts the system clock. This of course has a terrible effect on chronyd, with frequency and offsets jumping all over the place.

I have reported the bug to Apple so hopefully it will be fixed in some forthcoming patch release of macOS 10.13

It does not seem to be possible to permanently stop/disable the timed service via the launchctl mechanism.

In the interim, the only solution I have been able to come up with is to enable automatic time adjustments and then set the NTP server name to some fictitious name that has no IP address. After changing the name, then once again disable automatic time adjustments. timed will continue to run but fail in its attempts to get valid NTP responses. Its ugly, but it seems to work.

Bryan Christianson
***@whatroute.net