Disable Hibernation in Windows 11 and Reclaim Up to 25 GB

One hidden file, one command, and up to 25 GB back on your C: drive — instantly.

There's a file on every Windows machine I've ever set up or maintained that most users have never seen — hiberfil.sys. It sits quietly at the root of the C: drive, marked as a protected system file, and it silently reserves several gigabytes whether you ever use hibernation or not. If you want to disable hibernation in Windows 11 and take that space back, the fix takes one command and about two minutes.

How much you get back depends on your RAM, not your storage habits: Windows sizes this file at roughly 40% of installed memory. That's about 6 GB on a 16 GB machine, nearly 13 GB on a 32 GB one, and around 25 GB on a high-memory workstation — reclaimed the moment you press Enter.

In this guide, I'll show you the exact commands I use, how to verify the space was actually returned, the one feature you give up in exchange (Fast Startup), and the middle-ground option that lets you keep it while still freeing about half the space.

I'm Mostafa Amaan, and on Valley4Techs I write practical Windows and infrastructure guides built on real-world experience. Open an elevated terminal — let's reclaim some space.

What Does Disabling Hibernation in Windows 11 Actually Do?

That's the whole operation in a nutshell — no registry editing, no third-party "cleaner" tools, and nothing in your personal files is touched. But before you run the command, it's worth understanding what hibernation does, why the file is so large, and which of the three options below actually fits the way you use your PC:

1. Full disable — delete hiberfil.sys completely and reclaim the maximum space (the right call for most desktops).
2. Reduced hibernation — shrink the file to about 20% of RAM and keep Fast Startup working.
3. Leave it on — the sensible choice if you hibernate a laptop daily or rely on Fast Startup's quick boots.

I cover all three in detail below, but if you already know you never use hibernation, you can jump straight to the step-by-step instructions.

Hibernation vs. Sleep: What's Actually in hiberfil.sys?

These two power states get confused all the time, and the difference matters because it explains exactly why that file is so big. Here's the short version before we break each one down: sleep keeps your session in RAM, hibernation copies it to your drive.

How Sleep Mode Works

When you put your PC to sleep, Windows keeps everything you're doing — open apps, documents, browser tabs — in RAM while the rest of the system drops into a low-power state. Waking up takes a second or two, but the machine keeps drawing a small amount of power the entire time it's asleep. Let a laptop sleep for days on a low battery and you'll come back to a dead machine, because sleep is an ongoing power cost, not a one-time write.

How Hibernation Works (and Where hiberfil.sys Comes In)

Hibernation takes a different route: before powering the PC fully off, Windows writes the entire contents of RAM to hiberfil.sys on your system drive. Power draw drops to a trickle — barely more than a shut-down PC — and when you turn the machine back on hours or days later, it reloads that file into memory and puts you exactly where you left off. The trade is simple: hibernation spends disk space instead of electricity, and the file has to be at least as large as everything that could be in your RAM. That's why Windows defaults it to about 40% of your installed memory rather than 100% — a compromise that covers the vast majority of real sessions.

How Much Space Does hiberfil.sys Take in Windows 11?

The file scales with your RAM, not with your usage — a point that surprises a lot of people. A fresh Windows install on an empty machine reserves the same hibernation file as a workstation loaded with virtual machines. Here's what the default 40% setting translates to in practice:

Approximate values based on Windows' default sizing — your exact numbers can vary slightly by system configuration.

This is why the payoff is so lopsided. On a small 16 GB laptop, disabling hibernation frees a welcome but modest ~6 GB. On a memory-heavy desktop, you're looking at a four-digit megabyte figure that rivals an entire game installation — space handed back the instant the file is deleted. On a 2 TB drive it's not a crisis, but it's still the single largest one-command win available on most systems, which is why it earns its place in my full C: drive cleanup playbook for Windows 11.

One more thing worth knowing: every time the PC hibernates, the entire contents of RAM are rewritten to the SSD. On a desktop that hibernates daily with 32 GB of RAM, that's a 12+ GB write cycle repeated for a feature nobody in the room is using. It won't kill a modern SSD, but there's no reason to pay that cost for nothing — and it's the same reason I recommend the software-side cleanup before blaming the hardware whenever a machine feels sluggish.

How to Disable Hibernation in Windows 11 (Step by Step)

Everything happens in an elevated terminal — no downloads, no registry edits. I've also included a before-and-after verification step, because "did it actually work?" is the first question I get whenever I recommend this to colleagues. Follow the four steps in order.

Step 1: Record Your Free Space Before the Change

Open Terminal (Admin) — right-click the Start button and choose Terminal (Admin), or search for Command Prompt, right-click it, and pick Run as administrator. First, check the file exists and see how much free space you're starting with:

dir C:\hiberfil.sys /a
fsutil volume diskfree C:

The first command confirms hiberfil.sys is present and shows its exact size; the second prints the precise free space on C:. Look for the Total free bytes line and note the number — this is your "before" reading.

Recording the "before" numbers: hiberfil.sys size on disk and total free bytes on C:.

Step 2: Run the Command to Disable Hibernation

In the same elevated terminal, type the following and hit Enter:

powercfg /hibernate off

That's it. powercfg /h off is the shorthand for the same command, and both do the identical job: Windows immediately deletes hiberfil.sys and stops offering hibernation. There's no restart required and no confirmation dialog — the space is yours again the moment the command returns.

Step 3: Verify the Space Was Actually Reclaimed

Run fsutil volume diskfree C: again and compare the Total free bytes line with your "before" reading. The difference should land almost exactly on the expected figure for your RAM size from the table above. This is also the honest way to confirm the gain on any machine — the Storage page in Settings is notoriously misleading here because of rounding.

The before/after comparison: the gap between the two readings is your reclaimed space.

Step 4: Confirm Hibernation Is Gone from the Power Menu

Open Control Panel → Hardware and Sound → Change what the power buttons do, click Change settings that are currently unavailable, and check the shutdown settings list. The Hibernate option will no longer appear alongside Shut down, Restart, and Sleep — a quick visual confirmation that the feature is fully off. The shutdown /h command also stops working, which is expected.

Proof in the power menu: Hibernate no longer appears in the shutdown settings list.

The Trade-Off: Fast Startup Goes With It

Deleting hiberfil.sys costs you more than just the hibernate option. Fast Startup — the Windows feature that makes cold boots quicker by saving part of the system state to disk at shutdown — relies on the very same file. With it gone, every full shutdown falls back to a normal boot, which usually takes a few seconds longer.

Here's the part most guides skip: Restart is unaffected. Fast Startup only applies to shutdown, not restart, so if your routine is to reboot for Windows updates and otherwise leave the machine on (as mine is, on every workstation I administer), you lose almost nothing. And if you shut down rarely enough that those few extra seconds don't register, the trade is a bargain: tens of gigabytes for a handful of seconds on the rare occasions you actually power off.

If you're the opposite type — someone who shuts the PC down religiously every evening — pause before running the command. The reduced mode in the next section was practically designed for you. For more ways to tune what happens when your PC powers off, my guide to scheduling a shutdown timer in Windows pairs nicely with this one.

The Middle Ground: Reduced Hibernation Frees Half the Space and Keeps Fast Startup

If losing Fast Startup is a deal-breaker, don't disable hibernation outright — shrink it instead. Windows supports a reduced hibernation mode that cuts the file from about 40% of your RAM down to about 20%. With hibernation still enabled, run this in an elevated terminal:

powercfg /hibernate /type reduced

On a 32 GB machine, that single switch converts a 12.8 GB file into a 6.4 GB one — you keep Fast Startup and still claw back roughly half the space. The catch is that full hibernation becomes unavailable while reduced mode is active, and on very memory-constrained systems a reduced file may occasionally fail to capture an unusually full session. Heavy multitaskers should weigh that against the savings. To go back to the default behavior later, run powercfg /hibernate /type full.

How to Re-Enable Hibernation Later (If You Change Your Mind)

Nothing about this change is permanent, which is exactly why it's a safe experiment. If you ever want hibernation back — say you've moved the setup to a laptop, or you've decided those fast hybrid boots were worth it — one command recreates everything:

powercfg /hibernate on

Windows regenerates hiberfil.sys at its default size immediately, the Hibernate option returns to the power menu, and Fast Startup comes back with it. Expect the disk space to drop by the same amount you gained — that's the deal working in reverse, not a bug.

Should You Disable Hibernation? A Quick Decision Guide

The right answer depends less on specs and more on how you actually work. I've summarized the recommendations I give in real deployments below — find your setup and follow the matching row.

On the machines I manage, the desktop rows dominate, which is why hibernation is one of the first settings I touch on a new build — right alongside the telemetry changes in my guide to disabling Windows 11 telemetry. The space is better spent on the projects and files that actually justify occupying the drive.

Reclaim Your Space — One Command at a Time

Disabling hibernation in Windows 11 is one of those rare tweaks that costs you nothing you'll miss on most desktops and returns up to 25 GB instantly: measure first with fsutil volume diskfree C:, run powercfg /hibernate off, verify the gain, and move on. If Fast Startup matters to you, the /type reduced variant keeps it alive while still returning half the space — and everything reverses with powercfg /hibernate on whenever you change your mind.

If your C: drive is still tighter than you'd like after this, don't stop here: the complete C: drive cleanup guide walks through the DISM component store cleanup and the rest of the built-in tools that stack on top of this win. Run the command, check your before-and-after numbers, and tell me in the comments how much you got back.

Frequently Asked Questions

These are the questions I hear most often from users and colleagues about hibernation and hiberfil.sys. If yours isn't here, leave it in the comments and I'll add it.