A:
I'm pretty sure that you can, but you'll have to reformat the HD first. The file system that is pre-stalled on the HD is Mac Only. The xbox should do the work for you though...From the xbox support site:
When you connect a compatible external storage drive, Xbox One will prompt you to format the drive and walk you through setting it up to store games and apps.
The basic requirements for storing games and apps on an external drive are:
Has capacity of 256 GB or more
Uses USB 3.0.
Devices that don’t meet these requirements will be treated as media storage, such as for music or video. If you have a storage device that does meet these requirements for game and app storage, you can cancel the format to use it as a media device.
If your console doesn’t recognize your external drive, see Xbox One console doesn’t detect external storage.
If you cancel the format when you connect the storage device, you can still set it up as a storage device later. Here’s how:
Press the Menu button, select Settings, select System, then select Manage storage.
Select your storage device, then select Format for games & apps