The 20190521 snapshot brought an update to systemd, after which systemd.timesyncd.service fails to start.
● systemd-timesyncd.service - Network Time Synchronization
Loaded: loaded (/usr/lib/systemd/system/systemd-timesyncd.service; enabled; vendor preset: disabled)
Active: failed (Result: exit-code) since Thu 2019-05-23 08:33:39 BST; 2min 38s ago
Docs: man:systemd-timesyncd.service(8)
Process: 679 ExecStart=/usr/lib/systemd/systemd-timesyncd (code=exited, status=238/STATE_DIRECTORY)
Main PID: 679 (code=exited, status=238/STATE_DIRECTORY)
May 23 08:33:39 Orion-15 systemd[1]: Failed to start Network Time Synchronization.
May 23 08:33:39 Orion-15 systemd[1]: systemd-timesyncd.service: Service has no hold-off time (RestartSec=0), scheduling restart.
May 23 08:33:39 Orion-15 systemd[1]: systemd-timesyncd.service: Scheduled restart job, restart counter is at 5.
May 23 08:33:39 Orion-15 systemd[1]: Stopped Network Time Synchronization.
May 23 08:33:39 Orion-15 systemd[1]: systemd-timesyncd.service: Start request repeated too quickly.
May 23 08:33:39 Orion-15 systemd[1]: systemd-timesyncd.service: Failed with result 'exit-code'.
May 23 08:33:39 Orion-15 systemd[1]: Failed to start Network Time Synchronization.
May 23 08:33:41 Orion-15 systemd[1]: systemd-timesyncd.service: Start request repeated too quickly.
May 23 08:33:41 Orion-15 systemd[1]: systemd-timesyncd.service: Failed with result 'exit-code'.
May 23 08:33:41 Orion-15 systemd[1]: Failed to start Network Time Synchronization.
For anyone else hit by this the solution is:
Remove the symlink “/var/lib/systemd/timesync”
Delete “/var/lib/private/systemd/timesync”
Then restart the service.
(Needs only to be done once, subsequent re-boots are OK.)