Originally posted by scriptasylum
Hello,
What exactly is the hybernate.sys file anyway? I've noticed it on my system and while I don't really need the space, I don't like wasting it. What happens if I delete it?
Hibernation is a feature that let's you power down your system without closing any programs. It is similar to what you see on many laptops.
It basically saves all your current memory contents to disk (hybernate.sys) then you can completely power down the system. Next time you turn it on, hybernate.sys is read back into RAM and everything was exactly how you left it (you don't even have to save your word document (although I would recommend you do)).
Whether it is faster or not depends on the size of the RAM contents, but it's always convenient.
NT has good enough memory management make this feature useful, but you wouldn't want this feature in a 9x OS because they really need to have a fresh boot on regular intervals.
If you decide you don't want this feature and want to free up some disk space, you
can't just delete the file. Instead go to Control Panel/Power Options/Hibernate and disable it.
I can't remember whether or not you then have to manually delete the file.