How to Delete hiberfil.sys by Disabling Hibernation in Windows 11

What hiberfil.sys is and why deleting it directly fails

When you hibernate, Windows writes the entire contents of RAM to hiberfil.sys and powers off; at the next boot it reads the file back and resumes exactly where you left off. The same file powers Fast Startup. In that mode Windows closes all sessions but writes the kernel session to disk, which shaves a few seconds off every cold boot.

The file is marked as a protected operating system file and locked by the system, so File Explorer refuses to delete it even for administrators — and if you strip the attributes by force, Windows simply recreates the file at the next boot. That is why the correct approach is not to delete the file but to switch the feature off. Without hibernation enabled, the file has no reason to exist.

• Default size: about 40% of installed RAM — 3.2 GB at 8 GB, 6.4 GB at 16 GB, 12.8 GB at 32 GB
• Used by both hibernation (S4) and Fast Startup
• Hidden and locked: visible in File Explorer only after unhiding protected OS files
• powercfg /h /type reduced shrinks it to roughly 20% instead of removing it
• powercfg /h off deletes it completely; powercfg /h on brings it back

Disabling hibernation step by step

Right-click the Start button and choose “Terminal (Admin)” — in older Windows 11 builds the entry is called “Windows PowerShell (Admin)”; both work. In the terminal window, type powercfg /h off and press Enter. There is no output and no progress bar, but the command works instantly: hibernation is disabled, hiberfil.sys is deleted and the space is freed the same second. Verify by checking free space on C: or by running powercfg /a, which lists the available sleep states — Hibernation should be gone from the list.

Two related commands are worth knowing. powercfg /h on reverses the change and recreates the file — that is the answer if you ever need hibernation back. And powercfg /h /type reduced is the middle ground: it keeps Fast Startup working with a file of about 20% of RAM but removes full hibernation — useful on desktops where you want the faster boot without spending 6 GB on a hibernate image.

What you give up — and when you shouldn't do it

Disabling hibernation costs two things. Fast Startup stops working, so cold boots get slightly longer — barely noticeable on an SSD, more visible on hard drives. And the Hibernate option disappears from the power menu, which matters mostly on laptops: hibernation is the only power state that survives an empty battery with your session intact. If you use a laptop and sometimes close the lid for days, keep hibernation or at least the reduced type.

One group benefits from disabling it beyond the disk space: dual-boot setups. Fast Startup leaves the Windows partition in a semi-hibernated state, which makes Linux mount it read-only or refuse to mount it at all — a classic “why can't I write to my Windows disk from Linux” mystery. Turning hibernation off is the standard fix for that, and it removes the multi-gigabyte file in the same stroke.

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