I have Windows 7 Ultimate installed on my PC. The C drive has a capacity of 20 GB and I have only a few applications installed. Still, the drive shows as being almost full up to its capacity and keeps prompting for a disk cleanup.

Even after a disk cleanup the story continues. I have even tried using some Registry cleaner applications to free up space, but no luck.

How can I regain disk space?

  • 8
    registry cleaners aren't going to free up space and disk cleanup will only work to a degree (really only if you have a lot of temp files). What you need to do is find out what is taking up your space (music, movies, etc) and get rid of what you don't need. 20 GB is not that much space anymore, especially with modern media and games.
    – MaQleod
    Aug 22, 2011 at 20:04
  • as i have mentioned i have hardly few applications installed on C still dont know whats wrong.. Aug 22, 2011 at 20:10
  • 2
    How could this be NARQ?
    – soandos
    Aug 22, 2011 at 20:17
  • @Legendlovermaddy: Welcome to SuperUser. If one of the answers below answers your question, please click the checkmark next to it. Thank you.
    – soandos
    Aug 22, 2011 at 20:24
  • 1
    Really 20GB? I don't think i've seen one of those since the platters were the size of a 22" monitor lol. Seriously though, just buy a new hard drive. 1TB is about $50 now and days. You can clone the hard drive and install it back in the computer. This will save everything and everything will be just as it was.
    – Matt
    Aug 23, 2011 at 10:38

10 Answers 10


The story is pretty simple. Windows 7 Ultimate is about 10GB. If you have any backups, hibernation enabled, or pretty much anything, you won't have much space left. The only thing to do is get a bigger drive.


EDIT: To address the comment of the OP, if they are different physical drives, I would just install windows 7 on the largest one (if this will be your primary OS, else at least on something with about 50GB or so of free space).
If there is really only one drive, but it is partitioned, you can add space to your partition with drive management (just search for in the box on the pearl menu).

  • 2
    +1 Given that the Windows 7 install requirements list about 16GB of disk space required you're not going to be able to fit much in the remaining 4GB these days.
    – Mokubai
    Aug 22, 2011 at 20:07
  • 3
    The good part is that hard drive space is amazingly cheap now. A new terabyte drive can be found for the cost of lunch for four at McDonald's.
    – CarlF
    Aug 22, 2011 at 20:07
  • ohh, my other drives have pretty much free space available.. can i merge it with c drive so that i can solve this issue. if yess advise procedure how to merge.. thanks Aug 22, 2011 at 20:08
  • Edited answer to address comment.
    – soandos
    Aug 22, 2011 at 20:12
  • 1
    If you have 3 partitions (say C, D, E), copy everything from D to E, then in the disk manager, delete D, and expand C to the fill the space left by D. Windows 7 has this ability built-in, otherwise you would need a tool like gparted. Aug 24, 2011 at 2:39

Here are two things that I usually do when I need disk space (I'm using W7UL with 40GB SSD):

  1. Release disk space disabling your hibernation and delete hibernation file:

    Click on your Windows Start Button / Type "cmd" on the search box, then type powercfg -h off and press Enter (see screenshot below).

    enter image description here

    This option will disable hibernation, delete the hiberfil.sys file, and remove the Allow hybrid sleep and Hibernate after Power Options under Sleep.

  2. Use the Windows Disk Cleanup utility:

    Click on your Windows Start Button / All Programs / Accessories / System Tools / Disk Cleanup. Select what you want to clean and press OK. (I recommend you cleanup your temporary files included on one of the options). See the screenshot below:

    enter image description here


Your hard drive just barely meets the minimum requirements for installation. Here are Microsoft's requirements for Windows 7. Simply put, you need more capacity.


Look at WinDirStat; it's a Windows clone of KDirStat.

WinDirStat will give you a directory tree map of which files are on your Windows partition, allowing you to quickly see what's taking up most of your space and potentially delete large unnecessary files.

I'm a Linux user and haven't tried Windows 7 yet, but older versions of Windows always used to have large unnecessary video files (TV shows; movie clips) and other bloatware that you could reclaim ~1-2 GB of space by deleting. However, with only a 20GB hard drive and Windows 7, your best bet may be to choose a lighter OS or buy another hard drive.


As already mentioned I would suggest using CCleaner as it will not only remove temporary system files, but also temporary files from many programs (of which are supported). It also supports deleting of selected System Restore Points, which you may have a ton of since they are created during certain driver/software installs and/or during some Windows Updates. I would delete all but the last one (which CCleaner does) assuming your system runs stable as-is. You can also do it from within Windows, but you can only delete all Restore Points, which IMHO is a bit dangerous.

Otherwise you can try removing unused programs/services installed by Windows:

  1. Open Control Panel
  2. Click Uninstall a program
  3. On the right-side Turn Windows features on or off
  4. De-select apps that you don't use. If you're not sure about something, leave it or Google it.

enter image description here


Run CCleaner.

There are a lot of Windows Update and temporary files that you can remove, but I also agree with everyone that you need another hard drive for your data; Windows 7 is going to just about max out that 20GB drive.

  • 1
    +1 for CCleaner. Awesome program, been using it for years
    – TheLQ
    Aug 24, 2011 at 18:05

I would recommend that you make the OS partition at least 60 GB. I've done several Windows 7 installs and the "base" install takes nearly 20 GB in my experience.

  • 1
    I think this could be in new disks of windows 7 but the disk I've takes 8-10 GB.
    – avirk
    Aug 23, 2011 at 1:39
  • If differs. The 32 bit install takes a few GB less space. A windows 7 64 bit install takes almost 14GB.
    – Hennes
    Jul 2, 2015 at 10:41

There are numerous options as has been pointed out above but generally when I need to create a minimum size install I will pick and choose options from these two guides that fit the installs needs:




I followed the process to decompress the drive from here and it worked.

Right click on Drive C and click properties. In properties, select "Compress drive to save disk space" and unselect "Allow files on the drive to have contents indexed in addition to file properties". Press Apply. The process with take a couple of hours on my SSD drive.


  • 1. Your link is to compress a drive and not decompress 2. You should never compress the whole drive ("The Windows folders include critical system files including the NT loader knowns as NTLDR (NTLDR.dll), ntoskrnl.exe, ntfs.sys, winload.exe (depending on your Windows version) If you compress any of these critical files, you will run into the error bootmgr is compressed or missing and you will have to repair your OS using the computer repair options." 3. We don't like link only answers.
    – DavidPostill
    Jul 2, 2015 at 11:22
  • I have updated the steps. I will update the thread if i run into any issues. Its a windows compression so I assume it would take care of those files, not sure though.
    – biplav
    Jul 2, 2015 at 11:46

Answer above helped to clear 6GB from C drive (on win 7 U) with hibernate turned Off.

> powercfg -h Off

While for the 'Disk Cleanup', try 'Clean up system files'option in the System Tools > Disk Cleanup utility to remove windows update related back up files, which would have taken up significant disk space.

Alternatively, windows update files can be removed from command line (cmd.exe run as administrator user):

> net stop wuauserv
> rmdir %windir%\softwaredistribution  /s /q
> net start wuauserv

This second option cleared about 1.5GB of disk space for me :)

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