--- title: "DuplicateDuster — Local File Deduplication" description: "Finds exact duplicate files and folders by SHA-256 hash across any number of drives. You choose which side may be cleaned. 100% local processing." url: "https://royalsoftworks.com/products/duplicate-duster/" source: "https://royalsoftworks.com" format: "markdown" note: "Markdown rendering of the HTML page at `url`. Same content, same canonical URL." --- [All products](https://royalsoftworks.com/#products) Finds files you saved twice # Find the copies. Keep one. Take your space back. You tell DuplicateDuster which folders hold the originals and which ones are allowed to lose files. It compares them byte for byte, shows you every exact copy — single files and whole folders — and only ever deletes from the side you pointed at. It runs on your own machine, and nothing is sent anywhere. [Get it free](https://royalsoftworks.com/download/) See it find them Windows · macOS · Linux — free tier scans without limit A B C A D E F B G C H A I D J F K E L G M H B N Example scan · duplicates found 0 Space reclaimed 0.0 GB Exact-match certainty 01 How it matches ## One method, and it's never wrong. DuplicateDuster hashes the actual content of every file with SHA-256. Two files with the same hash are byte-for-byte identical — there's no approximation, no scoring, and no false match. The filename never matters: a copy renamed or moved to a different folder is still recognised the moment its content matches. ### What it catches - Exact, byte-for-byte duplicates anywhere in the folders or drives you selected - Copies that were renamed — the match is on content, not the filename - Copies moved to a different folder or a different drive - Whole folders whose recursive contents are identical, reported as one finding - Any file type — hashing doesn't care what the file is ### What it doesn't - A file that was re-saved, re-encoded, or edited — even by one byte — won't match - There's no "similar image" or "near-duplicate" detection - Symbolic links are never followed and never reported — a tool that deletes files has no business resolving them - Zero-byte files are ignored: they all match each other, and removing them frees nothing We'd rather tell you the boundary than oversell it. 02 The safety model ## You decide which side is allowed to lose files. Most dedupe tools hand you a pile of matches and leave you to work out which copy was the real one. DuplicateDuster asks first. The source folders hold what you're keeping; the target folders are the ones being cleaned. Matches are only ever paired across the two, and only the target side gets a checkbox. Source · keep ### The library you trust Your photo library, the canonical project archive, the NAS share everything else was copied from. Nothing here is ever selectable, and nothing here is ever removed — it is shown alongside each match purely for context, badged _keep_. D:\\Photos\\2024\\ \\\\nas\\archive\\projects\\ Target · clean ### The mess you're clearing The old laptop's Desktop folder, three generations of manual backup, the downloads directory nobody has opened since 2022. Only these files can be selected, and only these files can be removed. E:\\old-laptop\\Desktop\\ E:\\backup-2019\\ · E:\\backup-2021\\ #### Folder matches, not just files When every file under a target folder also exists in the source, the folder itself is reported as a match — and only the topmost one, so \`photos/\` doesn't bury you in its own subfolders. #### System paths refused outright Windows, Program Files, /usr, /etc and their equivalents are skipped during the scan and refused again at delete time, whatever is selected. #### Empty folders cleaned up after Directories left empty by a cleanup are removed, deepest first — but only if they are genuinely empty. Anything still holding a file you kept stays. Explore DuplicateDuster ## Exact matching, explained — and proven safe. What it catches, where it's used, and exactly what happens to a file before it's removed. [Features ### What it does SHA-256 matching for files and folders, four reclaim modes, filters, and what it deliberately doesn't claim. View](https://royalsoftworks.com/products/duplicate-duster/features/) [Use cases ### By scenario Creative archives, backups gone wild, shared drives and photo libraries. View](https://royalsoftworks.com/products/duplicate-duster/use-cases/) [How it works ### Scan to space reclaimed The size pre-pass, the worker pool, folder matching, and the four ways to reclaim. View](https://royalsoftworks.com/products/duplicate-duster/how-it-works/) [Security ### Nothing leaves the machine Local-only processing, protected system paths, and what secure erase really guarantees. View](https://royalsoftworks.com/products/duplicate-duster/security/) [Whitepaper ### Technical reference Matching model, threading, folder signatures, and the reclaim implementations, in detail. View](https://royalsoftworks.com/products/duplicate-duster/whitepaper/) [FAQ ### Common questions Source vs target, folder matches, free-tier limits, and how secure erase really works. View](https://royalsoftworks.com/products/duplicate-duster/faq/) 06 Free and Pro ## Find every duplicate for free. Pay to clean at scale. Scanning, matching and the reclaimable-space report are unlimited on the free tier — the number it gives you is the real number, not a teaser. What Pro buys is acting on it: the free tier reclaims up to 50 files per run, Pro has no cap. ### Free Prove the number - Unlimited scanning across as many folders and drives as you like - SHA-256 exact matching, files and whole folders - Full reclaimable-space report, group by group - All four reclaim modes — recycle bin, permanent, secure erase, hard-link - Clean up to 50 files per run ### Pro Per seat, volume available Act on it - Everything in Free - No per-run cleanup limit — clear thousands of files in one pass - Whole-folder matches cleared in a single action - Online activation or an offline licence file for air-gapped machines ### See how much space is hiding on your drives. DuplicateDuster 1.0 is in free open beta for Windows, macOS and Linux. [Download](https://royalsoftworks.com/download/) [See pricing](https://royalsoftworks.com/pricing/)