\hiberfil.sys

[Jennifer]

This is a very large file that shows up unable to be
defraged. I have done a search on my hard drive to find
it, but it does not come up anywhere. Does anyone know
what this is? Thank you.

 

[John Barnett MVP]

It is the hibernation file. This is needed when you put your pc into
hibernation. If you don't use hibernation then i suggest you disable it in
the Power options (control Panel>Power options>Hibernation tab) By disabling
hibernation you will regain the space the file takes up. In my case almost
400MB.

 

[Earl F. Parrish]

This is a very large file that shows up unable to be
defraged. I have done a search on my hard drive to find
it, but it does not come up anywhere. Does anyone know
what this is? Thank you.

This file is created each time you go into hibernation. Since the
file is only read when you come out of hibernation, there is no
opportunity or need to defragment this file. The next time you go
into hibernation, a new file is created.