DiskLens

A fast, visual disk-usage explorer built for Windows.

Find the folders consuming your storage, drill into them instantly, and keep the interface responsive while the scan runs in the background.

Why DiskLens?

File Explorer can tell you that a drive is full, but not where the space went. DiskLens turns a directory scan into two complementary views:

• Treemap — folder size becomes tile area, making large consumers obvious.
• Ranked list — exact sizes and percentages make comparison easy.

Click any folder in either view to drill down. Breadcrumbs take you back to any parent without repeating the scan.

Highlights

Capability	What it provides
Responsive scanning	Disk traversal runs outside the WPF interface thread.
Bounded worker pool	Up to four directory workers scan concurrently without overwhelming the disk.
Adaptive concurrency	Low-core systems scale down; network paths use no more than two workers.
Fast navigation	An indexed result tree keeps folder drill-down effectively instant.
Light and dark themes	Switch the complete interface from the top action bar.
Safe traversal	Reparse points are skipped to prevent junction loops.
Honest results	Inaccessible entries are counted and shown instead of aborting the scan.
Zero installation	Uses built-in Windows PowerShell and WPF; no packages are downloaded.

Quick start

Launch from Explorer

Download or clone the repository, then double-click:

Launch DiskLens.cmd

Launch from PowerShell

powershell.exe -NoProfile -ExecutionPolicy Bypass -File .\DiskLens.ps1

Start by scanning a specific location:

powershell.exe -NoProfile -ExecutionPolicy Bypass -File .\DiskLens.ps1 -Path "D:\"

How to use it

1. Select a fixed drive and choose Scan now, or use Choose folder.
2. Follow live worker, folder, and elapsed-time progress in the status bar.
3. Click a treemap tile or folder row to inspect its direct children.
4. Use the breadcrumb bar to return to a parent folder.
5. Choose Light theme or Dark theme whenever you prefer.

Performance model

DiskLens combines a background PowerShell runspace with a native bounded worker pool:

WPF interface
    |
    +-- background scan runspace
            |
            +-- concurrent directory queue
                    |-- worker 1
                    |-- worker 2
                    |-- worker 3
                    +-- worker 4

Concurrency is intentionally bounded. This provides useful parallelism on modern SSDs without creating an unbounded task for every folder. Network paths are limited to two workers, and machines with fewer CPU cores automatically use fewer workers.

The treemap renders the largest 80 direct subfolders at a time to preserve smooth interaction in directories with thousands of children. The ranked list continues to show every direct child.

Privacy and safety

• Scans remain local; DiskLens has no networking or telemetry code.
• No file contents are opened or uploaded.
• Reparse points and junctions are skipped.
• Read errors are counted and surfaced in the summary.
• Closing the window cooperatively cancels active scan workers.
• The screenshot above was generated from built-in synthetic demo data and contains no real username, machine name, drive letter, or filesystem path.

Requirements

• Windows 10 or Windows 11
• Windows PowerShell 5.1 or newer
• WPF, included with supported Windows desktop installations

No administrator access is required. Protected folders may appear in the Unreadable count unless DiskLens is intentionally launched with elevated permissions.

Demo and screenshot mode

Contributors can open the privacy-safe sample dataset without scanning a disk:

powershell.exe -NoProfile -ExecutionPolicy Bypass -File .\DiskLens.ps1 -Demo

Regenerate the README cover:

powershell.exe -NoProfile -ExecutionPolicy Bypass -File .\DiskLens.ps1 `
  -Demo -ScreenshotPath .\assets\disklens-preview.png

Project layout

DiskLens.ps1              Application, scanner, themes, and demo data
Launch DiskLens.cmd       Explorer-friendly launcher
assets/
  disklens-preview.png    Privacy-safe GitHub cover screenshot

Current scope

DiskLens reports and visualizes storage usage. It deliberately does not delete, move, or modify scanned files.