Delete hiberfil.sys: Safe Steps & What It Does
Deleting hiberfil.sys is safe and can free up disk space, but you should not delete the file manually. Instead, disable hibernation through the Command Prompt, which removes the file automatically and prevents it from returning. This article explains what hiberfil.sys is, why it exists, and the safest ways to remove it.
What Is hiberfil.sys?
hiberfil.sys is a hidden system file that Windows uses to store the contents of your RAM when your computer enters hibernation. When you hibernate, Windows saves everything in memory to this file, then powers off completely. When you turn the computer back on, it reads the file to restore your session exactly as you left it. The file is located in the root of the system drive (usually C:\hiberfil.sys) and is protected by the operating system, so you won’t see it in File Explorer by default.
Why Is the File So Large?
hiberfil.sys is typically about 40% of your total installed RAM, but it can be larger or smaller depending on your system configuration and the hibernation settings. For example, if you have 16 GB of RAM, the file may be around 6 GB. Windows also uses this file for Fast Startup, a feature that makes booting faster by saving the kernel session to disk during shutdown. Because it must store the entire memory state, the file size is tied directly to the amount of RAM you have.
Can You Just Delete the File?
You cannot simply right-click and delete hiberfil.sys. The file is locked and protected by Windows, and even if you take ownership and force deletion, the system will recreate it the next time you hibernate or shut down with Fast Startup enabled. The only reliable way to remove it is to disable the hibernation feature entirely. This is done through a command-line tool, not through the Control Panel or Settings app.
How to Safely Disable Hibernation and Remove the File
The following steps work on Windows 10 and Windows 11. You will need administrator privileges.
- Click the Start button, type cmd, then right-click Command Prompt and select Run as administrator.
- In the command prompt window, type the following command and press Enter:
powercfg /h off - You should see no confirmation message, but the command will take effect immediately. The hiberfil.sys file will be removed automatically.
- To verify, open File Explorer, go to the C: drive, and check that hiberfil.sys is gone. You may need to enable Show hidden files in View options to see it.
If you want to re-enable hibernation later, run powercfg /h on as administrator. This will recreate the file with a default size.
What Do You Lose by Deleting It?
Disabling hibernation removes two features: Hibernate and Fast Startup. The Hibernate option will no longer appear in the Power menu. Fast Startup, which is enabled by default on most systems, will also be turned off. Fast Startup makes booting faster by saving a portion of the system state to disk on shutdown. Without it, your computer will perform a full shutdown each time, which may add a few seconds to boot time. Your regular Sleep mode is unaffected.
Alternatives: Reduce the File Size Instead of Deleting
If you want to keep hibernation but need more disk space, you can reduce the size of hiberfil.sys to about half of the default. This is useful if you rarely hibernate but still want Fast Startup. Run the following command as administrator:
powercfg /h /type reduced
This sets the file to a smaller size, but it may not support full hibernation—only Fast Startup. To revert to full size, use powercfg /h /type full. This is a good middle ground if you want the boot speed benefit without the large file.
Common Issues and Troubleshooting
Sometimes the command powercfg /h off does not remove the file immediately. This can happen if the system is using hibernation at that moment or if Fast Startup is still enabled. Try restarting your computer after running the command, then check again. If the file persists, ensure you are running the command as administrator—otherwise, you may get an error like An unexpected error occurred. Also, some systems with Modern Standby (also called S0 Low Power Idle) may still create a hibernation file even after disabling it through the command. In that case, you may need to disable Modern Standby in the BIOS, but that is rarely necessary for most users.
Frequently Asked Questions
Is it safe to delete hiberfil.sys?
Yes, it is safe to remove the file by disabling hibernation. You will lose the ability to hibernate and use Fast Startup, but no data will be lost. Your documents and programs remain intact.
How much space will I free up?
You will free up roughly 40% of your installed RAM. For example, with 8 GB of RAM, you might reclaim about 3.2 GB. The exact size depends on your system’s memory configuration and whether you have used the reduced type.
Why can’t I see hiberfil.sys in File Explorer?
The file is hidden by default because it is a protected operating system file. To see it, open File Explorer, go to the View tab, check Hidden items, and then uncheck Hide protected operating system files in the Folder Options dialog. Be careful when modifying system files.
Will deleting hiberfil.sys slow down my computer?
It may slightly increase boot time because Fast Startup is disabled. However, if you have an SSD, the difference is often negligible. Regular shutdown and startup will work normally.
Can I move hiberfil.sys to another drive?
No, Windows does not support moving hiberfil.sys to a different drive. It must remain on the system drive. You can only disable it or reduce its size.
Does disabling hibernation affect sleep mode?
No, sleep mode (standby) is separate from hibernation. Sleep keeps your RAM powered and does not use hiberfil.sys. Disabling hibernation only removes the Hibernate option and Fast Startup.
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