How to Determine Where All Your Free Hard Drive Space has Gone (Windows)

This guide will show you how to use a small and free App to quickly locate both large files and the type of files taking up the most space on your drive. That way you can figure out exactly what to delete in order to free up as much drive space as you need.

  1. Start out by downloading WinDirStat. WinDirStat is a Windows App that runs on “all current variants” of Windows, up to and including Windows 10. The installation is as straight forward as you’d expect – you click “next” a few times and you’re done. When it’s completed, launch it from your Start menu or Desktop.
  2. Select the drive you want to scan – typically this will be the C: drive. Click OK when you’re ready. Note: depending on the size of your drive, the number of files on it and the overall speed of your PC, this scan may take anywhere from a couple of minutes to… an hour (?). To speed up the process, close all other open Apps while the scan is running.
  3. selected C drive in windirstat

  4. While it runs, a small series of ‘pac-man’ animations will keep you entertained.

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  6. Once it’s done you’ll be presented with the main WinDirStat window. From here, locate a large ‘block’ in the treemap (that huge colorful series of blocks in the bottom section of the screen) and select it by clicking on it once.

    WinDirStat will identify that file and show you its location via the section in the in the upper-left corner of the screen. In the example below, the large file I selected was the pagefile.sys file. As you can see from the Description field in the upper-right corner of the window, this happens to be a System file – which means you almost certainly don’t want to delete it. When in doubt, always Google the file name.


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  8. Selecting a “block” of another color will show you a file of a different type. This time, when I selected a large ‘blue’ block, it turned out to be a large .MKV file – which is a movie. This is typically the kind of file you’ll want to identify – something safe to delete. Just make sure you’ve backed it up first!

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  10. Another way to identify files to delete is to find a specific ‘type’ of file. For example, .FLAC files (uncompressed audio) tend to be quite large. So by selecting the extension .flac from the menu in the upper-right section, all of the FLAC files are ‘highlighted’ in the Treemap (see screenshot below). Now you can identify potential FLAC files to delete.

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  12. It’s a pretty slick little App – ‘click around’ and discover some of its other features!