WinDirStat

WinDirStat is an application that you can use to analyze the space occupied by files and folders on your hard drive.
After you initialize the program with the plain and simple interface, you can select a drive (individual or all local drives) or folder to get started.
WinDirStat takes a few moments to scan the respective drive or folder (depending on its size), after which you can check out the percentage, size, last date and time of modification, attributes, as well as the total number of items, files and subdirectories.
Once the scanning process finishes, you can view the extension of files which take up the most space on the disk, as well as a description, color, size and percentage.
The colors are necessary for examining the visual representation of these results, which is displayed on the bottom part of the screen.
If you access the right-click menu, you can copy a selected path to clipboard, open Explorer or Command Prompt at that location, as well as view properties and delete files.
In addition, you can empty Recycle Bin, zoom in and out (when it comes to the visual representation), select a parent, as well as show free space and unknown items, and configure program settings (e.g. change the interface language, enable to cross file system boundaries, disable Pacman animation, show time spent during the scan, set a user defined cleanup).
The program takes up a high amount of system resources and contains a well-drawn help file. We haven't come across any difficulties during our tests since WinDirStat didn't pop up any errors.
All in all, WinDirStat is an excellent tool for analyzing disk usage and we strongly recommend it to all users who want to thoroughly clean up their computers.