This is on a fresh Windows 10 install, using a 60 GB SSD and a pair of 1 TB HDD's. No folders were moved off the SSD (C:\) outside of what Windows supports. (That is, I moved all user folders to the HDD that I was allowed to, and installed all programs to the HDD that I was able to.)
I enabled hibernation via the Power Options > System Settings section in the control panel. The C:\ drive has 25 GB free space; well more than enough for hiberfil.sys to work normally. When hibernating, the system appears to behave normally and hibernate as it should.
When booting from a hibernated system, the computer POSTs normally and then brings up the Windows 10 logo and loading screen briefly before powering off very suddenly. I have to turn on the system again, and when I do, it boots normally but the hibernation state is lost.
I've attempted disabling fast startup, which seems to have no effect. I've updated my video drivers to 15.9 beta, but I recall this being a problem on 15.7 as well. Full system specs are in my profile. This machine was running Windows 7 in the past before upgrading, but I had to run a fresh install of Windows 10 after encountering some problems. (So the system is currently on a fresh install.) Google is also currently unable to deliver any relevant results for this problem. Windows Update reports being up to date.
Edit: Additionally, this has never been a problem on Windows 7. The SSD is in decent condition too, and has not exhibited any problems.
Edit: This problem was happening on shutdown and restart as well. I disabled fast startup, which corrected the problem when shutting down. Here's a summary of the behavior now:
Shutdown, no fast startup: Able to start up normally without any unexpected behavior.
Shutdown, fast startup enabled: Computer immediately shuts off just after reaching the Windows boot screen. Has to be powered on again and then will boot normally.
Hibernate, regardless of fast startup setting: Same behavior as above.
Conclusion: From my understanding, fast startup acts as a subset of hibernate. Windows 10 is not able to properly hibernate the driver(s) and/or some other system state. I might have to go through the drivers via process of elimination to see what's causing the problem.
Edit: I found the problem!
So despite no BSOD ever appearing, I ran the BlueScreenView utility to view the system dumps. Got the driver IRL not less than or equal error, found that it was from sptd2.sys; the SPTD (a SCSI bypass driver) I installed with Daemon Tools. I found a separate uninstaller for the driver and got rid of it; it's not something I need anyway. (Lots of Google searching will find you these utilities and solutions.)
Would be nice if it showed an error or BSOD in the first place! I was about to go whack-a-mole on the drivers, but I would've never found the root cause.
Anyway, hopefully this helps someone Googling around or something.