How-To

What Is hiberfil.sys and Why Is It Using So Much Hard Drive Space?

By Austin Krause

Updated October 23, 2023

This quick tip will free up GB’s worth of space on your hard drive or SSD.

You might have noticed that somewhere on your Windows 10 system, there are a few GBs of unaccounted-for space. One of the places that this vanishing space is hiding is in the hiberfil.sys file. Besides being a big space hog, hiberfil.sys has another function for Windows 10 that you may not even use.

Update: This post has been updated for Windows 11

What Is hiberfil.sys and Why Is It Using So Much Hard Drive Space?

The Windows feature is called Hibernation. In the power settings and the mobility options for many PCs, going into Hibernation mode is a typical default setting. The general idea behind Hibernation mode is that it allows you to shut down your computer completely while saving your work/session so you can quickly turn your computer back on and pick up right where you left off. Now, on a notebook, you can probably already see where this would be useful, particularly when you run into situations when you can’t afford to shut down but your battery is running low. Or perhaps the plane is about to land, and you need to shove your computer in your backpack quickly.

Try Sleep as an Alternative

If you’re using a desktop computer, however, hibernation becomes a much less useful tool for obvious reasons, which could be why Microsoft includes Sleep Mode, which is tailored for desktop PCs. In sleep mode, your computer will go into low-power mode and essentially “pause” most essential services like turning off your hard drives, cranking your CPU way down, and shutting down fans. While it doesn’t save quite as much power as Hibernation, it does allow you to bring everything back up within seconds, whereas Hibernate usually takes 30-60 seconds to start up and get going again.

Make sense? Do you agree we should get rid of Hibernation mode on that new/old desktop of yours? Okay, good. Let’s reclaim our precious hard drive space.

Note: By default, hiberfil.sys is a hidden and protected system file, so just to be able to see it we’ll need to tweak a few settings first.  Let’s do that now.

How to Find hiberfil.sys in Windows 10

1. Press the Windows key
2. Search for File Explorer Options and click it.
3. Go to the View tab and disable Hide protected operating system files (Recommended).
4. Now, browse to C:\ (or whatever your system drive is) and sort by file size.

Lo and behold, you’ll likely find a giant file called hiberfil.sys. (Editor’s note: On my computer, this amounted to about 2.5 GB of space.)

How To Delete hiberfil.sys And Save Space On Your Windows 10 Machine By Disabling Hibernation

Remember, doing this will disable Hibernate on your PC.  You can easily re-enable it, but Hibernate mode won’t work until you do.

5. Open up the command prompt as an administrator. To do this, click Start and then type in cmd and right-click the program link, then select Run as administrator from the context menu.

5. In the command prompt, type in “ powercfg.exe –h off “ and press Enter.

If later you want to re-enable this feature, just use “ powercfg.exe –h on “ in the command prompt.

Now just restart the computer, and hiberfil.sys should be gone! If it is still there, you should now have permission to delete it.