TL;DR

WinDirStat: treemap of which folders and extensions own the disk (like du, visual).

On Linux, when a disk fills up, the reflex is:

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du -xh --max-depth=1 / | sort -h
# or ncdu /

On Windows there is no decent du in the box. Explorer → Properties is slow and opaque. The tool I use in the lab and on desktops: WinDirStat — free, open source, interactive treemap.

Think of it as du on steroids: scan a drive or folder and see where the space went, not only how many GB.

What it does (beyond summing bytes)

ViewUse
Directory listSort by size, like du | sort -h
Extension statsSee whether .iso, .vmdk, .log, or .bak dominate
TreemapEach rectangle is a file; area is size; color is type
Largest files / duplicatesObvious delete-or-move candidates

The project site documents multithreaded scans, direct NTFS scanning when available, dark mode, and Explorer integration.

Quick use

  1. Download the installer (or portable build) from windirstat.net / the project’s GitHub releases.
  2. Run as Administrator if you are scanning all of C:\ (permissions on Windows, other user profiles, etc.).
  3. Pick a volume or a specific folder (D:\VMs, C:\Users\…\AppData).
  4. Wait for the scan. Large disks take time; this is not du on a tmpfs.
  5. In the treemap, zoom into the fat block. Open the folder in Explorer, or delete from the UI only when you know what it is.

When to use it

  • Disk is “full” and you do not know whether it is Downloads, hibernation, pagefile, ISOs, or VM snapshots.
  • Before/after cleanup of a profile or a share.
  • Showing a non-CLI person what owns the space (the treemap sells itself).

What it is not

  • It does not replace du/ncdu on Linux or on a NAS over SSH.
  • It is not a magic cleaner: deleting System Volume Information, WinSxS, or “big” databases because they look large will break the host.
  • A full C:\ scan on a file server with millions of files can take a long time; narrow the root.

Mental map

WorldTool
Linux CLIdu, ncdu
Windows GUIWinDirStat
macOSDaisyDisk / OmniDiskSweeper (another family)

Download and docs: https://windirstat.net/.