What is Hiberfil.sys? – Removing hiberfil.sys

If you are a Windows XP user, then more likely you already experienced this, if not… then at least you know what to do. Its like one day, while searching a file or cleaning the hard disk, you will find a huge file, approximately 250 MB to over 1GB and  you don’t know who on earth save that to your computer. Let me guess… is it hiberfil.sys that is normally located at C:\hiberfil.sys? Ooh … don’t look at me that way… I’m not the genius that save that to your pc without your knowledge.

Of course since its eating a lot of space in your hard drive, the first thing that you want to do is delete it. But it is NEVER a good idea to delete files that you don’t know. So if you want to know more… then read on. 😛

Windows XP has a feature that is not very well documented and it will be totally new to users of older systems such as Windows 95 or 98. This new feature is called Windows hibernation.

Hmmm… since Windows XP got a lot of feature that is not well explained and documented and far ahead than the older systems such as Windows 95 or 98… users of the old  system might as well be lost. FYI, this new feature is the Windows Hibernation.

Here’s how it works:

After you  are done using your computer and you want to take a break, take a bath, eat or nap… there is another thing you can do instead of shutting down and restarting your computer.  That is pressing the hibernate button, wherein Windows takes a snapshot of everything running on your system, copies it to the hard drive and then turns off most of your hardware. To wake up from hibernation you normally move the mouse or hit the spacebar on the keyboard.

Well, it  is supposed to be a quick shortcut or power saving option that allows you to leave your PC  without turning it off until you are ready to work again. However, most people is more at ease shutting it down than hibernating it. For users who use drive imaging to backup their system, the hiberfil.sys file can  cause the backup files to bloat…making them larger and therefore slower to copy or restore.

Hibernation temporarily ‘freezes’ your computer when the PC or the user becomes inactive, causing all the tasks running constantly (eg downloading files) to freeze.  Sound unhelpful? However it can be handy if you want you and  the computer to sleep after a task has completed (such as creating a video).

Now you know the  role of hibernation – so the question that is left  is the hiberfil.sys file and why is it so big? Hibernation takes everything in memory and writes it to your hard drive as the hiberfil.sys file. The amount of hyberfil.sys can be the amount of your computer’s memory. If you have 512MB of memory, then hiberfil.sys will be about 512MB. If you have 1GB, then it wll be around 1GB.  Hmmm… I know what you’re thinking. One thing you have to know is that even if you don’t use hibernation, hiberfil.sys will still take up this huge amount of disk space. The  only way to remove the file is to turn off the hibernation feature because by default, hibernate is activated automatically when XP is installed.

Here’s how to do it:

  • Click on Start then go to Control Panel
  • Open Power Options
  • Select the Hibernate tab, un-check the ‘Enable hibernate support’ check box, and then click Apply.
  • Restart your computer. It will automatically delete hiberfil.sys.