Two hidden system files in the root of C:\ quietly consume gigabytes: pagefile.sys (virtual memory) and hiberfil.sys (the hibernation image). They serve different jobs, so the safe answer differs. The page file should usually be left to Windows; the hibernation file is the one you can remove if you don't use hibernate or fast startup:

powercfg /h off

Run that in an elevated Command Prompt and hiberfil.sys disappears, reclaiming several GB.

TL;DR

  • pagefile.sys is virtual memory: an overflow area for RAM. Keep it managed by Windows.
  • hiberfil.sys stores your full RAM contents so the PC can hibernate; it's roughly 40% of installed RAM.
  • Safest single win: powercfg /h off removes hiberfil.sys entirely (disables hibernate and fast startup).
  • Don't disable the page file outright; it can cause crashes and breaks crash-dump capture.
  • Both files sit at C:\, are hidden, and shouldn't be deleted in File Explorer.

What is pagefile.sys and should I touch it?

pagefile.sys is the Windows page file, a chunk of disk used as overflow when physical RAM fills up. Windows sizes it automatically (System managed), often 1-8 GB depending on RAM and workload.

Leave it alone in most cases. If you must change it, do it through the GUI, not by deleting the file: open sysdm.cpl, go to Advanced > Performance > Settings > Advanced > Virtual memory > Change, and set a custom size or let the system manage it. Disabling it entirely is risky: low-RAM machines can crash, some apps demand a page file, and you lose the ability to capture a crash dump.

What is hiberfil.sys and can I remove it?

hiberfil.sys holds a snapshot of everything in RAM so Windows can power off completely during hibernate and restore your session instantly. It also backs fast startup. Its size is typically about 40% of your installed RAM, so 16 GB of RAM means roughly a 6 GB file.

If you never hibernate and don't rely on fast startup, remove it:

powercfg /h off

To bring it back later:

powercfg /h on

You can also shrink it instead of deleting it, keeping hibernate available at a reduced size:

powercfg /h /size 50

What Windows does natively, and where it stops

Windows manages both files for you. The page file is auto-sized and grows or shrinks with demand, and the hibernation file is created and maintained whenever hibernate or fast startup is enabled. You rarely need to intervene.

Where it stops: Windows will not delete the hibernation file just because your disk is low, and it won't ask before reserving 40% of your RAM in disk space. There's no setting in Storage Sense for either file. To reclaim that space you must run powercfg /h off yourself, and to cap the page file you must open the virtual-memory dialog manually.

What this cannot do, and what to leave alone

Don't try to delete pagefile.sys or hiberfil.sys from File Explorer; they're protected system files and Windows will recreate or refuse them. Always use the proper tools (sysdm.cpl for the page file, powercfg for hibernation).

Know the trade-offs. Turning off the page file can destabilize a low-RAM PC and disables memory dumps, so don't do it just to save a gigabyte. Running powercfg /h off also turns off fast startup, which is why some laptops boot a little slower afterward, and you lose hibernate as a low-power sleep option. These files aren't bloat or leftovers; they're working storage, so only change them deliberately.

Want the bigger space hogs? See how to find the largest files on Windows 11 without third-party apps, and to understand another big system folder, read what is the AppData folder and can I delete it.

FAQ

Is it safe to disable the page file to save space?

Generally no. On low-RAM systems disabling pagefile.sys can cause app failures or crashes, and it stops Windows from writing crash dumps. If space is tight, set a smaller custom size via sysdm.cpl instead of turning it off.

How much space does powercfg /h off free?

Roughly the size of hiberfil.sys, which is about 40% of your installed RAM. On a 16 GB machine that's around 6 GB. The exact figure depends on your hibernation file type setting.

Will turning off hibernation slow my PC?

It can affect boot slightly because powercfg /h off also disables fast startup. Cold boots may take a few seconds longer, and you lose hibernate entirely. Sleep (standby) still works normally.

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