Function Of hiberfil.sys File And How To Remove It

It happens to most users of Windows XP. One day you are searching for a file or cleaning up the PC's hard drive and you encounter a huge file - hiberfil.sys. Normally located at C:\hiberfil.sys, its size can vary from 250MB to over 1GB. You try to delete the file - it's not a good idea to delete files you don't understand - but Windows won't oblige anyway.

But, if you can't see this file, it doesn't mean that you didn't activated hibernation functon. First, make sure that you have unchecked "Hide Protected Operation System Files (Recommended)" option. Here's how to do it:

- Open Windows Explorer
- Click at Tools menu, and after that click Folder Options sub menu
- Click at View Tabs
- Unchecked "Hide Protected Operation System Files (Recommended)" option
- Click Apply Button and Click Apply To All Folders button

Windows XP has a feature that is called Windows hibernation. Instead of shutting down and restarting your computer, Windows takes a snapshot of everything running on your system, copies it to the hard drive and then turns off most of your hardware. In theory, it is supposed to be a quick shortcut or power saving option that allows you to leave your PC in suspended animation until you are ready to work again. Hibernation temporarily 'freezes' the computer when the PC becomes inactive, so it won't work if you have tasks running constantly (eg downloading files). However it can be handy if you want the computer to sleep after a task has completed (such as creating a video).

To wake up from hibernation you normally move the mouse or hit the spacebar on the keyboard. When you boot up from hibernation mode, the Operating System can read this file and get running a lot faster as apposed to a cold boot when it has to look around for installed hardware, installing drivers and so-on and so-on. Nothing is lost during a power service outage when hibernating. Therefore, great for laptops that get plugged in-and-out all the time. Suspend mode has no such file, everything stays in RAM which depends on power. Not so great for laptops running on low batteries.

Hibernation takes everything in memory and writes it to your hard drive as the hiberfil.sys file. If you have 512MB of memory, then hiberfil.sys will be about 512MB. If you have 1GB, then the file will be around 1GB. So, it's the same size as your RAM Memory Size. The important point to remember is that even if you don't use hibernation, hiberfil.sys will still take up this huge amount of disk space.

But, the presence of the Hiberfil.sys file will prevent Disk Defragmenter from performing a thorough defragmenting operation.

The way to remove the file is to turn off the hibernation feature (by default, hibernate is activated automatically when XP is installed). Here's how to do it:

- Open the Windows Control Panel
- Double-click Power Options
- Click the Hibernate tab, de-select the 'Enable hibernate support' check box, and then click Apply.
- Restart your computer and hiberfil.sys will be automatically deleted.

If you change your mind in the future and would like to use hibernation, go to the Windows Help and Support Center and search for 'enable hibernation'.