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

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

1
2

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)

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

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