I've had this issue for quite a while with my HP Split x2 now where you'd simply try shutdown Windows, however after it has shutdown you get the blank screen, but it does not power off the machine.

Recently (in the last week) I've had this issue happen to my main computer too which is a custom built PC, either since an update or from an unsafe shutdown, not sure which.

The only fix for this is to turn fast shutdown off which solves the issue on both my laptop (HP Split x2) and my PC. There should be a better fix for this though. So is there some steps I can take to diagnose it or to see if any hybrid files are corrupt or such? I have a feeling it is a hardware issue with my HP Split x2 but it's extremely unlikely that my custom built PC has hardware faults too.

Both machines are running Windows 8.1 Pro.