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#11
If you run the command without administrator privileges (from an "ordinary" command prompt), you will get an error saying you don't have the right privileges.
You didn't mention that, so I assume you ran it as an administrator.
If you notice no difference in disk free space, I can only assume it was already disabled.
I just tested it on my own machine--turning it on and back off.
I immediately noticed the difference when I did a right click on the drive in Explorer and checked free space.
I have no explanation if you are using it correctly.
Try this: enter the command "powercfg -h on". That turns hibernation on. See if your free space decreases. If it does, you are doing things correctly and you can then enter "powercfg -h off" to turn it back off.
What did you find with System Restore?