Technetium: A Portable Windows Utility Toolbox Built From Scratch With C++ and Qt

The problem I kept running into

Every time I needed to rename a batch of files, clear out junk from my disk, or convert a folder of images to another format, I ended up either doing it manually or installing yet another bloated utility app — most of which come with ads, forced installers, or background telemetry I didn't ask for.

The open-source alternatives that do exist are often either abandoned, poorly maintained, or trying to do too much at once. So I decided to build my own, focused on exactly the handful of tasks I actually repeat often, nothing more.

That project became Technetium — a free, portable Windows utility built entirely with C++ and Qt Widgets.

Design goals from day one

No installer. Unzip, run the .exe, done.
No ads, no telemetry, no dark patterns.
Safety first for anything destructive. Deleting files automatically should never happen silently or instantly.
Small, focused feature set rather than trying to be an all-in-one system tool.

With that in mind, here's what's inside.

Feature breakdown

1. Batch Rename with full undo history

Select a batch of files, apply prefixes, suffixes, sequential numbering, or find-and-replace rules, and preview the resulting filenames before committing anything.

What makes this more than a basic renamer: every operation is logged persistently (last 25 operations, saved to disk, surviving app restarts), and each one can be undone individually. If a file was since moved, deleted, or locked by another process, the undo process simply skips it instead of failing the whole batch — a small detail, but one that took a few iterations to get right.

2. System Cleanup across 11 categories

Scans and clears:

Temporary files
Recycle Bin
Browser cache
Windows Update cache
Thumbnail cache
Prefetch data
Memory dump files
Shader cache
Delivery Optimization files
Windows Error Reporting files
Leftover driver installation files

Sizes are calculated and shown before deletion, and every category can be toggled independently.

3. Scheduled Cleanup — the feature I spent the most time on

This is the part of the project I'm most proud of, and also where I hit the most interesting bug.

The idea: let the cleanup run automatically on a schedule (daily, weekly on specific weekdays, monthly on a specific date, or a simple "every N days" interval) — but do it safely. When the scheduled time hits, the app:

Scans the selected categories first.
Shows a system tray notification.
Waits a full 60 seconds, during which the user can cancel.
Only then moves the files to the Recycle Bin — never permanent deletion through the automated path.

The bug: my first implementation of calcNextRun() tried to do two jobs at once — computing "the next scheduled time to display in the UI" and "deciding whether to run right now" — using the same function. Because the function always projected forward from the current moment, the condition if (now >= next) inside the scheduler check could never be true, even when the scheduled time had clearly passed. The fix was splitting it into a pure calculation function (computeNextRun(after)) and a separate function that computes-and-persists the next run time to disk (recomputeNextRun()), so the actual trigger check compares against a stored value instead of recalculating a constantly-shifting target. Classic case of one function trying to serve two different callers with incompatible needs.

One limitation I'm upfront about: if the PC is fully shut down (not sleeping), there's no way for a background scheduler to fire — Windows just doesn't support that without BIOS-level wake timers, which felt like overkill for this project. On next launch, the app checks if a run was missed and catches up if so.

4. Image Format Converter

Batch-converts a folder of images (regardless of original extension) between PNG, JPG, BMP, and ICO, using QImageReader::canRead() to silently filter out non-image files rather than erroring out.

A few details that mattered more than I expected once real testing started:

Filename collisions (e.g., photo.png and photo.jpg both converting to .jpg) needed automatic _1, _2 suffixing instead of silently overwriting one of them.
ICO export only supports a single fixed resolution per file (16–256px) — not a multi-resolution bundle like dedicated icon tools produce. I decided this tradeoff was acceptable for the scope of the project rather than implementing multi-size ICO packing.

5. Basic multi-language support without rewriting the whole codebase

The original translation system was a simple Translator::t(viText, enText) call sprinkled throughout the codebase — fine for two languages, but not scalable to more.

Rather than refactor every call site (which would have touched hundreds of lines across the project), I kept the existing t(vi, en) call signature completely untouched everywhere else, and changed the internal logic of Translator::t() instead:

Vietnamese and English still return directly as before.
For six additional languages (Chinese, French, Spanish, Arabic, Russian, Hindi), the English string is used as a dictionary key to look up a translation. If no entry exists, it silently falls back to English instead of breaking or showing blank text.

This was a deliberate tradeoff: full coverage for two languages, partial (and growing) coverage for the rest, achieved without touching the rest of the codebase. Translation contributions for the secondary languages are welcome.

Tech stack

Language: C++
UI: Qt Widgets (Qt 6)
Build system: CMake
Compiler: MinGW 64-bit
Platform: Windows only (for now)

Licensing note

Technetium is source-available under a non-commercial license (PolyForm Noncommercial 1.0.0) — free to use, modify, and share for non-commercial purposes. Commercial use requires reaching out directly.

What's next

Still on the table for future iterations:

Windows Explorer right-click context menu integration (open a folder directly into a specific tab)
A file-lock finder/unlocker built on the Restart Manager API
Deeper translation coverage for the secondary languages

Check it out

This is a solo side project, built incrementally in my spare time — so bug reports, feedback, and translation contributions are genuinely welcome.

GitHub: github.com/qptqpt199-prog/Technetium

If you find it useful, there's a donation section in the README (currently set up for Vietnamese bank transfers / e-wallets via QR code — international donation options may come later).