In many of these forums people ask why their Apple videos will not stream anymore, and by now, most of us know it is because Apple tightened their policy on streaming their DRM protected videos. This policy has been confirmed again this week by comments from a forum moderator at the Seagate forum on Dec 19th, who said in a thread:
"ITune DRM protected videos are currently not playing on iOS 7.2.1 and iOS 8 devices when the files are saved to a GoFlex Satellite, Seagate Wireless, Seagate Central or LaCie Fuel as they had been with prior versions of iOS. We are investigating this issue with Apple to determine if we can restore this functionality and will offer a software update as soon as possible. We are investigating the issue for a solution.
Also, since this change came from Apple themselves, you may also find it useful to contact Apple and find out if they have any ETA on resolution of the issue."
Just an FYI that the problems are not just with WD drives and devices. All companies are affected by this move by Apple.