conflicting advice on removing hiberfile

[thx-1138]

...the only further thing that comes to mind is shutdown /s /f /t 0
However, some people online seem to suggest that this might not be enough with Win 8.1 / Win10,
and suggest...powercfg.exe /hibernate off instead.

Googling any of the 2 aformentioned messages just leads me to (not really many actually) threads in regards to...
Windows' intrinsic weirdness / endless loops & eventually...full-reinstall.
"Windows is hibernated, refused to mount. Operation not permitted."
"Windows Preinstallation Environment does not support Hibernate."

...and more or less the same suggestions that have already been made above.
The only other things would be to also try running chkdsk, sfc /scannow etc etc...
Kinda doubt they'll do the trick, but you never know.

So if still nada after all the above, personally, i'd just bite the bullet, backup the files using a live stick, and format.

[vansloneker]

...grab a Windows 10 installation cd / stick, open a command prompt with it , then run powercfg.exe /hibernate off

Here are my results:
Hibernation failed with the following error: the request is not supported.

The following items are preventing hibernation on this system.
Windows does not support Hibernate during the upgrade Process.
Windows Preinstallation Environment does not support Hibernate.

Well apparently Windows is in a process of upgrading. This is possible since last upgrade was delayed and ...
You tried to disable hibernate on the running installation Windows booted from USB or DVD. I can imagine this is not possible.

[thx-1138]

...i'm not entirely certain myself either if powercfg.exe /hibernate off can be run successfully from the Windows live environment,
however shutdown /s /f /t 0 certainly does though...