Yaaaaaay! After spending hours trying to get the Shareport Utility to recognize (and then connect to) the external USB backup drive connected to my DIR-825, I stumbled across your post. Downloaded and installed the software and...VOILA! Everything worked the way it used to before I installed the Windows 8.1 SP. I can't understand why the fix would be out there but D-Link wouldn't have it available on THEIR support website.
Thank you, thank you, and thank you again!