WinDirStat reads the whole directory tree once and then presents it in three useful views:
The directory list, which resembles the tree view of the Windows Explorer but is sorted by file/subtree size,
The treemap, which shows the whole contents of the directory tree straight away,
The extension list, which serves as a legend and shows statistics about the file types.
Coupling. Select an item in the directory list: The treemap highlights it; and vice versa.
Zooming.
Built-in cleanup actions including Open, Show Properties, Delete.
User-defined cleanups (command line based).
Works with network drives and UNC paths.
'Create disk usage report' option.
'Submit bug report/Feedback' option.
Online help.
setup.exe.
Language can be set to Czech, Dutch, Estonian, Finnish, German, English, Spanish, French, Hungarian, Italian, Polish and Russian.
Just have a look at the Translation website if you want to help or if you want to know more.