Windows 10 Hiberfil.sys Taking Too Much Space: Shrinking or Removing the Hibernation File Safely

While hunting for what fills your C: drive, you show hidden system files and spot a file called hiberfil.sys that is several gigabytes in size, sometimes as large as half your installed memory. You try to delete it, and Windows refuses. When Windows 10 hiberfil.sys taking too much space worries you on a small SSD, it helps to know what the file does before removing it.

Hiberfil.sys is the hibernation file. When a PC hibernates, Windows saves the contents of memory into this file so it can restore your open programs after the power is fully off. Fast Startup, which is on by default, uses the same file to speed up booting.

Because it must hold a large part of your memory, the file is big by design. On a PC with 16 GB of RAM, it can easily take 6 GB or more.

You cannot delete it like a normal file, but you can shrink it or turn hibernation slot off, which removes it automatically.

Possible Causes

The file grows large for these reasons:

• Hibernation is enabled, so Windows reserves space for memory contents.
• The PC has a lot of RAM, which increases the file size.
• The hibernation file type is set to Full.
• Fast Startup relies on the file even if you never hibernate manually.

The file is recreated at every start-up while hibernation is on, so deleting it through other tools does not help.

Quick Fixes to Try First

Decide whether you need hibernation.

1. If you never use Hibernate and do not mind slightly slower start-ups, you can turn it off.
2. Right-click Start and open Windows PowerShell (Admin) or Command Prompt (Admin).
3. Type powercfg /hibernate off and press Enter.
4. Restart the PC.
5. Check that hiberfil.sys has disappeared and the space is free.

Turning hibernation off also disables Fast Startup, which some people prefer for fewer start-up problems anyway.

Advanced Steps for Stubborn Cases

Keep Fast Startup but shrink the file.

1. In an administrator prompt, type powercfg /hibernate on if you turned it off.
2. Type powercfg /h /type reduced and press Enter.
3. This keeps a smaller file used only for Fast Startup, while removing the full Hibernate option.
4. To set a custom size, type powercfg /h /size 50, which uses 50 percent of RAM, the minimum allowed.
5. Restart and check the new file size.

To bring the full feature back later, type powercfg /h /type full.

Before You Go Further: Keep Your Files Safe

Laptops left in sleep can lose unsaved work if the battery runs out, and hibernation protects against that. Save your work before shutting the lid when hibernation is off.

Conclusion

Hiberfil.sys is large because it stores memory contents. Turn hibernation off with powercfg if you do not need it, or use the reduced file type to keep Fast Startup while saving space.