How to figure out where your hard drive space went with WinDirStat

Hard drive prices keep dropping and capacities keep ballooning--but brand new huge hard drives somehow fill up just as fast as their cramped ancestors. Use free tool WinDirStat to figure out where all that space went.
Published: Apr 1, 2008
Author: Jordan Running
Related OS: XP / Windows / Vista

When I was in high school I saved money from my after-school job for months in order to buy a 6.4 gigabyte hard drive. I thought I couldn't possibly fill that much space, but of course I did in a matter of months. Nowadays a gigabyte of hard drive space is not one but three orders of magnitude cheaper, and new computers ship with 120GB, 250GB, or even larger hard drives. Yet, thanks to the proliferation of digital music, video, and photos, modern hard drives are even easier to fill up.

Shrinking drive spaceA couple times a year while browsing my files I catch, out of the corner of my eye, the free hard drive space gauge in My Computer and say, "Whoa, where'd all my free space go?" There's two ways to figure it out: I could browse through all my files, trying to spot bloated folders and wasted space, or I could use a tool like WinDirStat, a free utility that draws a visual "map" of your hard drive and all its contents. I'm sure you won't be surprised that I highly recommend the latter.

Once you've downloaded and installed WinDirStat, it's pretty easy to use, but can be a little intimidating, so I'll walk you through it. When you first start WinDirStat it will present you a list of all your hard drives and attached storage devices (like USB drives) and their available space. On most computers the C: drive is where your programs and documents are stored, so you'll probably want to start with that (if you'd rather, you can choose an individual folder or do all drives at once).

WinDirStat - Choose drive

When you click OK, WinDirStat will start scanning your hard drive, and you get to watch a cute little Pac-Man animation as it reads the contents of each folder on your hard drive and their sub-folders and so on. When it's done you'll be presented with a "map" wherein each file is represented by a colored rectangle.

WinDirStat - Main window

The most important thing you need to know is that a rectangle's area is relative to the size of the associated file. Big boxes are big files, little rectangles are small ones. Go ahead and click around a bit--don't worry, you can't break anything by clicking. When you click on one of the boxes you'll see two things happen up above: First, the directory tree on top will jump directly to the file whose rectangle you clicked on. The tree will show you what folder the file is in as well as information about it: its size, the last time it was modified, and how much space it takes up relative to other files in the same folder. Second, the color legend pane in the upper right will jump to show you the file's type. You can also do this in reverse: Clicking on a file or folder in the tree will highlight it on the map with a white border, and clicking on an item in the legend will highlight all files of that type and color on the map.

WinDirStat - Type highlight

Just by clicking around you can get a good idea of where the most space is being taken up on your hard drive--but don't start deleting files yet! You must be careful of what you delete, and how. For example, the biggest file on my hard drive is pagefile.sys, a system file that Windows needs in order to run. Of course, Windows would never let me delete this file, except by extreme means. Other files I could delete, however, but still shouldn't. One large file I found is called USA_CD.mad, which takes up more than half a gigabyte. But by looking at the tree pane I see that this file is inside the Microsoft Streets & Trips folder, itself inside Program Files. Streets & Trips is a program I use--in fact, my guess is that USA_CD.mad is the main data file that holds the maps for that program--so deleting the file would render the program useless.

The best policy is not to delete any file unless you know what it's for. One way to discover the purpose of a file is to simply type its name into a search engine like Google. Chances are good that among the first results will be pages that will give you hints as to what it's for.

When looking inside the Program Files folder and its sub-folders you might realize you have programs installed that you no longer want or use. However, it's best not to delete these files directly. Instead, you should go to the Control Panel (under the Start menu) and use Add or Remove Programs (Programs and Features on Windows Vista) to properly uninstall the programs.

You may also find one or more folders named Temp, and they may have quite a few files inside--perhaps thousands, and perhaps some very large ones. Temp stands for Temporary, and these are files that programs needed only temporarily. Unfortunately, many programs neglect to clean up after themselves and delete temporary files they no longer need, so Temp folders can get pretty cluttered. The good thing about these temporary files, however, is that it's usually safe to delete them. Don't delete the folder itself, just the files inside.

The main thing here is to use common sense. I repeat: Don't delete a file unless you know what it's for. Apart from the Temp folder, I recommend avoiding any files inside the Windows directory. Only delete things from the Program Files directory if you're unable to properly uninstall them and are absolutely sure they're not part of a program you use. When in doubt, ask Google, and if still in doubt, just leave it alone.

About Jordan Running

Blogger since 1999, Jordan Running went pro in 2005 and never looked back. Sometimes programmer, occasional photographer, and serial tinkerer, he decided to to switch to Linux in 2001 but just hasn't quite gotten around to it yet.

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