Tech Friday Tip: “What’s this hiberfil.sys?”

Posted By on December 15, 2006

I see a theme coming — maybe a ‘tech tip Friday? After posting the comment on how to save YouTube files yesterday, I received enough emails to suggest that at least a few readers liked what they read. One of the emails asked answer another question and I told him I would address it today. (I’m by no means a computer guru although prefer the ego boosting label – ‘power user’)
Hibernation file
Well here it goes — Jim R. said that his Win XP notebook had a full hard drive with the excess of bloated programs, digital photos and video content. He was cleaning out to create space and found a file that was huge that he could delete and suspected a virus or something. He asked how to delete a file in the root of his C:\ drive called “hiberfil.sys.” [C:\hiberfil.sys]

First, it not a nasty file or anything to be concern about except that it takes up precious hard drive space. It is the file that the Windows operation system uses to store information it needs to recover from the special shutdown state known as “hibernation.” Depending on what was running before hibernating your computer (or auto hibernating), the file can be pretty large — well over 1GB! What happens in XP is that your computer takes a snapshot of everything and records it to disk so that everything will come back when you restart from hibernation. (great feature in XP, BTW … and that’s a comment from a Macintosh lover)

The file basically contains everything that was in RAM (memory) and then writes it to the hard drive labeling it hiberfil.sys. This isn’t something you must use and there are way to turn it off if you don’t use 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.

What if you want to use it again? Well the easiest way is to go to the Windows Help & Support Center [click START and look near the SEARCH and RUN selections] by searching on the term ‘enable hibernation’ there will be instructions on how to reactivate the hibernation. Hope this helps those of you trying to save that precious disk space … but my advice for desktop users is to add a mega-giga external hard drive because files aren’t getting any smaller; besides, additional storage is pretty reasonable.


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  1. lacking in consistency, constancy, or visible order, disconnected; fitful: desultory conversation.
  2. digressing from or unconnected with the main subject; random: a desultory remark.
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