Contents
The Question
When I type powercfg -hibernate on in command line I get error: Unable to perform operation. An unexpected error (0x65b) has occurred: Function failed during execution. Why? How to fix it? I need to turn on hibernation in Windows 10. 
The solution
Just run cmd or PowerShell as admin: 
In this case you will be able to complete the operation successfully: 
That’s it!