This is a suggested fix for the Calender: Scheduler.
Currently, if you create an appointment and publish it, and then go back to divide it into slots, you cannot.
If you 'edit' the appointment, the dialogue box will come up, and the option to 'divide into slots' will be visible.
You can select a time-frame for the slots, and you can click 'Go'. But nothing will happen. No confirmation will appear.
In fact, nothing will happen, and if you click save after clicking 'Go', no modification will happen.
Instead, you have to delete your appointment and start again, ensuring that the division into slots happens *before* you publish the appointment.
My suggestion: enable editing of existing appointments so that division into slots works (as presumably intended).