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'm trying to determine what's eating almost half of disk on my Windows 7 Lenovo laptop but haven't been able to determine what. I read some of the answers on this site but none of the causes seems to be the cause of my problem.

What I've done so far:

  • Checked Windows' System Restore points but only minimum use, either way I deleted around 2GB if usage from there
  • Used WinDirStat and it came back with a total of 71.3GB usage at the root level
  • C Drives properties says 135GB being used out of 138 GB total, ie, 135 GB - 71.3GB = 63.7GB missing somewhere
  • No "Unknown" files reported by WinDirStat
  • Windows Disk Management utility doesn't report any unused partitions or unclaimed space
  • chkdsk comes out clean
  • Windows disk cleanup tool doesn't report anything big, just small stuff in the lower MB range
  • Lenovo backup tool hasn't been used nor there is a folder for the backup images

Any idea on what to look at and/or do?

EDIT: some additional info...


Disk Properties

Windows Disk Management

share|improve this question
If you don't mind losing your restore points, disable system restore, then re-check disk space, also Try this program, be sure to run it as – Moab Apr 21 '11 at 23:41
how big is the hard drive? also, how recent/old a model? – Journeyman Geek Apr 21 '11 at 23:42
Is this the problem? It's somebody else with a Lenovo laptop... apparently the Lenovo backup runs automatically even if you don't tell it to. If that was the problem, let us know and we can close this as a duplicate. – nhinkle Apr 21 '11 at 23:46
Hmm, perhaps you can also try some alternative to the great little tool WinDirStat? Another approach would be to e.g. use UnxUtil's or GnuWin's du port. – mousio Apr 21 '11 at 23:59
I used to use a program called Space Monger to check disk usage, but I'm not sure there's any reason it would work if WinDirStat doesn't. Might be worth a try though: (there's a newer version, but you have to pay for it) – user55325 Apr 22 '11 at 1:32

Well, I found what the problem was....

I installed SpaceSniffer and initially it gave me the same numbers as WinDirStat, but it also gave me some warnings about some directories it could not read, and among one of them was the Lenovo RRbackups backup directory that I thought it was not there since neither Windows Explorer nor WinDirStat showed.

So I ran the tool again but with Administrator privileges and voila, it found the big a... GB file inside the RRbackups directory that the Lenovo utility creates and that I couldn't see before. It turns out somebody ran the backup tool without me knowing.

I should have suspected that it was a permissions issue even though I was logged in with an account that is a member of the administrators group. Way to go Microsoft with Windows 7, an administrators group that doesn't have administrators privileges.... go figure...

Thanks all for the tips...

share|improve this answer
Welcome to 2006 when Microsoft released a security feature called UAC in Windows Vista (and every Microsoft OS since). It's a good thing. Educate yourself. – Ryan Bolger Apr 22 '11 at 21:17
Exactly, Linux has been using a similar (although better implemented) feature for much longer. – MaQleod Apr 23 '11 at 17:18

What works for me was lowering space for Previous versions of files (

  1. Click Start Icon
  2. Left Click on "Computer" and click on Properties
  3. Click on "System Protection" on left side
  4. Click on Disk and "Configure"
  5. Lower your quota
share|improve this answer

Assuming that there's files hidden away from the system, it probably should show up in rootkitrevealer - while it won't tell you filesizes, this should get you started on working out where the rest of the space went.

Alternately, i'd suggest running a windirstat equivilent off a linux live cd of some sort to bypass any OS level hiding of free space, and have similar graphical tools.

share|improve this answer

If Windows reports 135 GBs free out of 136 GBs, then trust it -- it's right. You can easily confirm this with the following DOS command:

  • dir C:\

At the end of the list of files, you will see an indication of how much disk space is free.

share|improve this answer
The op's problem is that he has 135GB used of 138 GB, but the files he finds only sum to 71GB – RJFalconer Apr 22 '11 at 0:33
Not sure what's your point. I know Windows is telling the truth, my problem is I have 63GB missing somewhere. – Tavo3 Apr 22 '11 at 0:44
@Tavo3: I think I know what's going on -- you have sparse files on your system, which WinDirStat is counting the "registered sizes" of, but Windows' built-in statistics report isn't counting this. A sparse file is one that has a big empty space in between and can be created by a program that creates a file (which always starts as 0 bytes), then writes a little bit of data at some point later in the file (e.g., if at the 1 GB marker, then the registered size will be 1 GB even though it doesn't actually use 1 whole GB). – Randolf Richardson Apr 22 '11 at 3:24
I have no idea why my response got -2 points. – Randolf Richardson Apr 22 '11 at 3:24
Because @Tavo3 wanted to know where the diskspace had gone and your answer doesn't indicate that. – Sathya Apr 23 '11 at 3:38

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.