SynthSize

When a drive fills up, Windows doesn't show where the space went. SynthSize lists every drive with its free and total space. Pick one, or type any folder or network (UNC) path, and SynthSize scans it in parallel. It shows each folder's size, file count, folder count, share of its parent and newest change, with the largest items always at the top.

From the result you can act right away: open an item in Explorer, cut or copy it to the Windows clipboard, rename it, show its Properties, rescan a folder or delete it. Delete goes to the Recycle Bin by default, Shift+Del deletes permanently after confirmation, and all sizes above a deleted item update without a new scan.

SynthSize is built to be safe. Symlinks and junctions are skipped, so nothing is counted twice and scans can't loop. The scan root and drive roots can't be deleted, and a recycle never silently becomes a permanent delete. An optional Explorer entry, "Analyze with SynthSize", starts a scan from any folder or drive.