Q. What is the impact of the When Xbox is off, turn off storage option?
A. The Xbox One has two power modes, connected on which allows it to start very fast (Instant-on) and an Energy-saving option. When using Instant-on there is also an option: When Xbox is off, turn off storage as shown below.
The impact of using this option when combined with the Automatically download updates and purchases is very important when you have an external hard disk you use to store games. Ordinarily when Instant-on mode is used any updates will download in the background even when the Xbox is turned off however if you have the When Xbox is off, turn off storage the external hard disk will be powered down and any games on the disk will not be updated while the console is turned off and will not update applications until you turn on the Xbox. Therefore if you use an external hard disk and want games to update when the Xbox is turned off uncheck the When Xbox is off, turn off storage option.