My son's Xbox One HDD failed after downloading an update. I did not have the technical know-how to mount and format a replacement drive for the Xbox One. I sought help from iFixit it.
It went awesome. The 1 TB replacement HDD I purchased from iFixit was formatted and had all the necessary Xbox software already installed. iFixit's HDD replacement guide was very easy to follow. I swapped the drive, the Xbox recognized it, and one update later the gaming resumed!
The Xbox One guide said HDDs purchased from iFixit are not formatted and do not contain the necessary Xbox applications. Mine was formatted and had the necessary Xbox applications. Not sure if I got lucky or the guide needs to be updated.