The unbookable period is the amount of notice you need for a client booking. This is used to prevent clients making short notice online bookings.
You can specify the amount of advance notice your business requires in order to accept a booking. The unbookable period can range from 0 hours (off) up to one week.
If you set an unbookable period of 2 hours and the current time is 2:00pm the client will be prevented from making a booking until 4:00pm.
Unbookable period excludes closed days
Selecting the option "Unbookable period excludes closed days" extends the unbookable period across your businesses closed days. For example your business is closed on weekends and you want to stop clients booking on the weekend for the Monday. Setting you Unbookable period to 1 day and selecting the option "Unbookable period excludes closed days" will restrict clients from booking on Saturday or Sunday for Monday times. Only Tuesday's and beyond will be shown for booking.
This restriction only applies to the public booking views, not to your Business Dashboard.