Behind Kleaner PRO 11: Five Engineering Decisions Explained

Decisions 1 and 2: allowlist first, self-managing systems off limits

The engine cleans only from a curated allowlist — update download caches, Delivery Optimization, error-reporting dumps, thumbnail and shader caches, Windows.old past its grace period, browser caches with the browser closed. Anything that merely looks temporary is not a target: a file gets cleaned because a Windows subsystem documented it as disposable, not because its name matched a pattern. Maintaining that list is slower than glob-matching the whole disk, and it is exactly the difference between a cleaner and a gamble.

The second decision extends the first: subsystems that manage their own data are untouchable. Prefetch traces, the WinSxS component store, the pagefile and the hibernation file stay out of every scan, because deleting from them costs performance or stability and buys nothing. We have spent years debunking those rituals in this blog; shipping a button for them anyway would be the cheaper business and the worse product.

• Allowlist-only targeting: nothing is cleaned without a documented Windows behavior behind it
• Hands off self-managing subsystems: Prefetch, WinSxS, pagefile, hibernation file
• Junction-aware scanning: reparse points are never crossed, so nothing is counted or swept twice
• Age thresholds in every volatile folder: files newer than the threshold are invisible to the cleaner
• Full preview before deletion: the exact file list, with sizes, before a single byte moves

Decisions 3 and 4: honest bytes and patient deletes

NTFS junctions and symlinks make the same bytes visible from several paths, and a naive scanner counts them twice — which is how tools report hundreds of gigabytes on a 256 GB drive. Version 11 tracks reparse points and counts each physical location once, which makes the numbers smaller and trustworthy. Smaller-but-honest is a hard sell in a market trained on big numbers; we decided it was the only defensible position.

The fourth decision is about time: volatile folders get age thresholds, and locked files are reported, never wrestled. A temp file created minutes ago may belong to a running installer, and a file an application holds open is not junk regardless of its path — the cleaner lists it and moves on instead of forcing handles closed. Deleting less than a competitor is only a weakness if you measure a cleaner by tonnage.

Decision 5: the preview is the product

Every scan ends in a complete, inspectable list of what would be deleted, per category with sizes, before anything happens. That sounds obvious, and it is rarer than it should be: most cleanup flows are built to move you from Scan to Clean before doubt sets in. We chose the opposite — the moment of hesitation is where a good tool proves it deserves trust, so in version 11 the list is the centerpiece rather than the fine print.

Underneath all five decisions runs the same test discipline: every allowlist change ships only after a pass over snapshot-equipped virtual machines, per-user and machine-wide contexts, and the localized path variants of every supported locale. None of this is glamorous. It is just the version of the job where we can explain, file by file, why anything was deleted.

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