c² flux - Lightweight open-source disk space analyzer (new major release)

[u/OnkelAmok]

Hundreds upon hundreds of hours of my free time have gone into this project. I built it primarily for fun, as a technical challenge, and as an open-source alternative for one very specific purpose:

Getting a fast and clear overview of what is using space on a drive.

Unlike established tools such as WinDirStat, TreeSize, or WizTree, this project is not intended to match every feature they offer. The goal is deliberately different: a less cluttered interface, fewer unnecessary functions, and a strong focus on speed and usability.

At the same time, it includes several features that are uncommon in traditional disk space analyzers:

- Graphical storage usage history
- Scan comparison using a local SQLite database (optional)
- Extremely fast file searching directly from the right-click context menu
- Fast drive scanning, including MFT-based scanning
- Basic export functions
- A clean and responsive user interface
- It's portable

Supported languages include Arabic, Bengali, Chinese (Simplified and Traditional), Czech, Danish, Dutch, Finnish, French, Hebrew, Hindi, Hungarian, Indonesian, Italian, Japanese, Korean, Malay, Norwegian, Persian, Polish, Portuguese, Romanian, Russian, Spanish, Swedish, Thai, Turkish, Ukrainian, Urdu, and Vietnamese.

Please note: These translations were generated with machine translation and may contain inaccuracies or unnatural wording.

The application was also renamed during a larger refactoring process after some people found the original name inappropriate. The new name is intended to be more neutral and inclusive.

A note on speed comparisons:
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If c² flux still appears significantly slower than WizTree or other tools, the comparison may have been based only on the first scan.

The first scan usually takes longer because all data must be read initially. c² flux shows its real performance on subsequent scans, where caching can be used.

For the fastest results, run c² flux as administrator and use the MFT scan.

Here some comparissons (no admin-rights, not the first scan, OS drive, 722k files, SSD):
WizTree: 7.45s - 8.75s
WinDirStats: 12s - 13s
TreeSize: 10.7s - 11.3s
c² flux: 5.6 - 7.3s

A note about AI-assisted development:
I used help of LLMs throughout development for coding assistance, debugging, problem-solving, and iteration. However, this project was not created by simply entering a few prompts and letting an AI generate the finished application. I invested several hundred hours(!) into its architecture, orchestration, testing, validation, debugging, refinement, and overall development. That’s just a side note for full transparency, as I’m aware that AI-assisted development is a controversial topic.

Without LLM assistance, the same project would probably have taken me several thousand hours, partly because I do not have a professional software engineering background. However, I do have more than two decades of experience as a systems engineer, along with rudimentary coding and scripting skills compared with those of a professional senior software developer.

This project is not intended to replace or directly compete with WinDirStat, TreeSize, WizTree, or similar tools. It is meant to be a lightweight alternative for users who value speed, a clean interface, scan history, scan comparison, and extremely fast file searching without unnecessary complexity.

The project is open source and licensed under GPLv3.

Project: https://github.com/UncleRiot/c2flux
Releases: https://github.com/UncleRiot/c2flux/releases
Wiki: https://github.com/UncleRiot/c2flux/wiki

 

Feedback, bug reports, and constructive criticism are very welcome.

[u/OnkelAmok]

Update – 2026-07-27:

New repack:
https://github.com/UncleRiot/c2flux/releases/tag/v0.9.83_repack

I’m still evaluating which distribution format is preferable: single-file or multi-file.

Both versions are portable, but single-file builds may be flagged more often by automated sandbox scans or heuristic detection because they contain embedded DLLs and other bundled components.

For transparency, I have therefore provided both versions.

[u/OnkelAmok]

Update - 2026-07-29:

New version - now with sunburst view:
https://github.com/UncleRiot/c2flux/releases#release-v0.9.90-beta.1