There was a time when installing CCleaner on a new Windows PC was as automatic as installing a browser. That reputation did not survive the years that followed. Security incidents, privacy concerns, persistent upsells, and an expanding array of features gradually eroded the software’s trustworthiness.

That led me to FluentCleaner, a free and open-source Windows cleanup utility from builtbybel. It tries to restore the straightforward bargain that made cleanup tools like CCleaner useful in the first place. It identifies disposable files, explains what they are, and lets you, the user, decide what gets removed.

CCleaner spent its reserve of trust

Trust is much harder to reinstall than software

CCleaner launched in 2003 and spent more than a decade as the Windows cleanup tool that many people installed almost by reflex. Piriform sold the company to Avast in July 2017, and not long after, attackers compromised its build environment and slipped a backdoor into a signed CCleaner 5.33 installer. Cisco Talos found the tampered binary and reported that 2.27 million users had downloaded it before it was pulled. Piriform and Avast were not the ones planting malicious code, but a supply-chain breach that large was always going to leave a scar.

The following year added another controversy. CCleaner 5.45 shipped with an Active Monitoring feature that turned itself back on after every reboot, even after users disabled it, sent analytics back to Piriform, and would not fully close from the usual interface. Piriform and Avast pulled that release after the backlash and reverted to the previous version. CCleaner is now owned by Gen Digital, alongside Norton and Avast.

I am not arguing that today’s CCleaner is unsafe. The current product has expanded into a broader suite that includes paid performance tools, driver and software updates, real-time monitoring, and scheduled cleaning. However, that sales pitch is far removed from the focused utility many users remember, which helps explain why FluentCleaner exists.

FluentCleaner puts the deletions back on the table

Show me the junk before you delete it

FluentCleaner is distributed through its GitHub releases page, and I tested FluentCleaner 26.07.02, released on July 15, 2026. Installation is pleasantly old-school: download the archive, extract it, and run FCleaner.exe. The app requires Windows 10 2004, build 19041, or later, along with the Windows App SDK 2.0.1 runtime, which you need to install separately if it is missing.

The layout made the first scan easy to follow. Navigation icons sit on the far left, application categories fill the next panel, and the larger pane on the right holds the results. Analyze stays in the lower-left corner, while Run Cleaner is in the lower-right corner. On my Windows 11 Pro 25H2 test machine with an Intel Core i7-7600U and 16GB of RAM, FluentCleaner detected 242 applications across 3,721 entries, grouped under familiar names such as Windows, Chrome, Firefox, Edge, Brave, Spotify, and Microsoft Store.

Most of those entries come from Winapp2.ini, a community-maintained database mapping applications to specific caches, temporary files, histories, and registry traces. FluentCleaner parses those definitions using its own engine, which matters now that CCleaner 7 is no longer compatible with the Winapp2 database.

My first analysis found 6.87GB of removable data spread across 43,915 files and 58 registry items. Chrome’s cache accounted for 1.96GB, Windows temporary files added 1.25GB, and Brave contributed another 659.3MB. FluentCleaner also exposed entries for the Recycle Bin, browser web storage, Windows Error Reporting, Windows Update files, and smaller application caches, rather than reducing everything to a single dramatic junk score.

Running the cleaner removed 43,204 files and reclaimed 6.81GB. That was useful storage, though it did not prove that my laptop had suddenly become faster. Around 68MB remained because Chrome and Brave were still open, and FluentCleaner warned that locked browser files would be skipped.

It also warned that its Firefox Browsing History rule could remove bookmarks because it modifies places.sqlite, which stores both. The latest database update disabled an Office entry that had removed pinned documents and corrected an Opera rule that could delete sessions and logins. Public rules and visible warnings make those problems easier to spot, but they do not make every cleaning definition safe.

FluentCleaner goes deeper only if you want it to

Power users will appreciate what’s under the hood

FluentCleaner has a built-in terminal that is designed for people who occasionally prefer commands to checkboxes. It displays basic system information, accepts clean, analyzed commands, and suggests matching entries as you type.

Most people will still be better served by the main Cleaner page because it provides the context needed to review categories, file totals, and warnings before deleting anything. The terminal is currently better understood as a faster interface for known operations than as a complete replacement for the GUI. Notwithstanding, repeatable commands could be useful if you’re experienced in building predictable maintenance routines, especially once you already know which definitions you trust.

FluentCleaner also includes an optional AI explanation feature, although the name initially made me suspicious. The AI does not scan the computer, choose files, or decide what should be removed. It only explains individual cleaner entries after the user requests it. Enabling the preview requires a personal Groq API key, and the settings page states that nothing is submitted without explicit action.

That could help with obscure Winapp2 definitions whose names reveal little about their purpose. However, I find the ability to inspect the underlying rules more valuable. FluentCleaner can expose the exact FileKey, RegKey, and detection instructions for an entry, giving me something concrete to evaluate rather than another confident paragraph generated by a model.

FluentCleaner also offers global exclusions, post-clean commands, cleanup history, and optional Winapp3 and Winappx databases in Settings. I left the aggressive databases undownloaded. Inspectable rules and visible warnings improve trust, but they do not make every available option sensible. FluentCleaner reports targeted registry traces defined by its rules, while deliberately avoiding the broad registry-cleaner routine that tries to classify miscellaneous keys as errors.

OS

Windows

Developer

Belim

Price model

Free

FluentCleaner is a free and open-source app for Windows that clears junk files, cache, and browser clutter without the bloat, ads, or trust issues that made you ditch CCleaner. 

Trust is the feature I wanted back

FluentCleaner has earned a permanent place on machines, and I would recommend it to Windows users over CCleaner. Storage Sense is still enough for routine maintenance, and FluentCleaner will not magically improve a PC that already has plenty of free space. Its value comes from wider application coverage, clearer rules, and the ability to inspect what it wants to remove before you let it touch anything.

That is the standard I would use to judge any cleanup tool. The important question is not how many gigabytes it claims to find, but whether it explains what those files are, shows what it plans to remove, and still gives you the final say.