Hibernation is a Windows feature that allows the computer to save the state of all running programs before shutting down fully. The computer can then resume from the saved state when it turns on again. Hibernation is designed to be a middle-ground between shutting down and going to sleep. The computer powers down as if it was shut down but saves its state as if it were asleep.
All data stored on the RAM when the computer hibernates is saved to the hard drive. This means a certain amount of space has to be left free on the hard drive at all times, just in case the computer hibernates at some point. This space is allocated to the “Hiberfil.sys” file. If you come across it – it’s that allocation amount. The size of Hiberfil.sys is approximately equal to the amount of RAM available in your system. So, if you’ve got 16GBs of RAM, 16GBs of your hard drive are unusable for this purpose.
You can reclaim that hard drive space if you want to by disabling the hibernation feature. To disable hibernation, you need to launch command prompt as an administrator by pressing the Windows key and then searching for “Command prompt”. Right-click, and then click “Run as Administrator”. If you are prompted to confirm that you really want to take this action, click “Yes” to continue.
Once in the command prompt, type the command “powercfg.exe /hibernate off” without the quotation marks and then press enter.
The command doesn’t return any output, so you won’t see any sort of reaction even if it works properly. Once the command has been run, you can close the command prompt by clicking the “X” in the top right corner. Please be careful and don’t otherwise type anything into the command prompt – it’s very easy to accidentally change something important!
Disabling hibernation runs the risk of data loss in the event of power loss – if your computer blacks out or a laptop runs out of battery and shuts down, you’ll lose some of what you were working on. If you want to re-enable hibernation, follow the same steps to open an administrative command prompt but run the command “powercfg.exe /hibernate on” instead.
Tip: If you want to confirm that the process works, restart your computer and check the hiberfil.sys file through a file explorer search. It should no longer be the same size as before, or even gone entirely.