Is there a way to disable the Online Store for a brief period of time?
The easiest way to do this is to just remove the link from your home page into the online store. Should you wish to remove access to certain customers, you can mark those customers inactive. Another alternative is to mark all of your products discontinued. Another alternative would be to go to the Settings section of your Order Management System and change the store type to be a B2B store, thus disabling all current B2C access, or vice versa should you wish to disable B2B and make only B2C available.