Super User is a question and answer site for computer enthusiasts and power users. It's 100% free, no registration required.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I recently used Defraggler to consolidate my free space areas on my D: drive preparatory to using Disk Manager to break my drive into two areas, one as my "data area" for Windows 7 (normally on my C: drive) and to experiment around with Windows 8. The Defraggler program works so well I ran it on my C: drive and I ended up with a lot of free space both on my C: drive and my D: drive. I was very happy. And then I woke up the next day and I've got virtually no free space left, something like 8 MB on my C: drive and about 3 GB on my D: drive. I then ran Wintree (which gives a nifty graphical representation of disk usage) and found I had a large page file and a large hiberfil. So I temporarily turned off hibernate and reduced the page file size to 2000megabytes and then rebooted so that both would take effect. It had no effect on the C: drive or the D: drive. That makes no sense to me.

What caused the free space on each drive to disappear, why doesn't the page file size being reduced and the hibernate file being turned off free up disk space to either the C: or the D: drive? Would it make sense to delete the two files in question and, if so, how do I go about doing that? Safe mode?



share|improve this question
up vote 2 down vote accepted

Defraggler doesn't free up space, it moves the data in sectors on your hard drive to make it more efficient for the hard drive to access.


This how-to shows you how to disable hibernation which in turn should remove the hyberfil.sys from your system -- I've done what it says and it worked for me.

As for the pagefile.sys, changing the page file to have a maximum size of 2GB and then rebooting should decreased the size of the page file -- assuming the page file was larger then 2GB. You can see the page file if you tell Windows to show you hidden and system files and then go to the root of the drive the page file is on.

My recommendation is to use WinTree again and find out what is using space or to get a bigger drive.

share|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.