WinDirStat is a free and open-source graphical disk usage analyzer for Microsoft Windows.

It presents a sub-tree view with disk-use percentage alongside a usage-sorted list of file extensions that is interactively integrated with a colorful graphical display (a treemap).

The project was inspired by SequoiaView, an application based on research done by the Visualization Section of the Faculty of Mathematics and Computer Science at the Technische Universiteit Eindhoven.

Reviewer Adam Pash praised WinDirStat for its ability to easily clean up unnecessary files, by stating: "If you find a large file or two taking up loads of space that you had forgotten was there and don't need, it's easy to clean up directly from WinDirStat. "

The minute you try to create your own user-configured cleanup routines you will quickly experience a complete lack of documentation, which makes the task rather challenging, if not impossible.