running HighSierra and hearing intermittent tritone sounds. I noticed that the sound happened at the same time as the previous day.
There are no user applications/scripts open when this happens, even after rebooting.
I would like to know if there is a way to find out where this alert sound is coming from and how to disable it.
EDIT - the sound seems to happen at the same time every day. At first it was at 9:30 pm, now it is happening at 3:30 pm daily.

