Find and remove duplicate files between two folders — without ever deleting something you don't already have safely backed up.
portoMatch is a Windows desktop app for people with files in two places: a working folder and a backup drive, a downloads folder and a photo library, a laptop and a NAS. It scans both, tells you exactly which files in the folder you want to clean up already exist in your authoritative copy, and lets you clear only those — nothing is ever deleted from the reference folder.
This repository hosts downloads only — portoMatch's source stays private, since the offline Pro licence key is derived in that source and a public copy would let anyone forge one. Windows builds are published here under Releases; nothing else in this repo runs or is installed.
Most "duplicate finders" happily delete whatever they flag. portoMatch is built the other way around: it only ever proposes removing a target file when it has confirmed a copy exists in the reference, it defaults deletions to the Recycle Bin, and it writes every removal to a CSV audit log. Deletions and moves are only ever proposed for target files; the only way anything reaches the reference folder is a file you explicitly promote into it.
- Pick two folders — a Target to clean up and a Reference that holds the authoritative copies.
- Compare — every target file is checked against the reference using multiple signals: file size, modification time, image/video dimensions, a fast BLAKE2b partial hash, EXIF image IDs, and a perceptual (dHash) image fingerprint.
- Review — results land in a list or a thumbnail gallery, grouped by how confident the match is, with a side-by-side preview and full metadata for any pair.
- Act — delete confirmed duplicates (Recycle Bin or permanent), move them to a trash folder, or promote them, with smart rules to keep the reference copy and clear the target.
| Tier | Meaning |
|---|---|
| Exact | Size, timestamp, hash and dimensions all agree |
| Strong | Almost everything agrees, one minor discrepancy |
| Review | Size plus one other signal — worth a human glance |
| Partial | Same image content, different file metadata |
| Visual | Visually similar image within a fuzzy threshold |
Gallery view — every target file as a thumbnail, so duplicates are obvious at a glance:
Detail list — sortable columns with sizes, dates, dimensions and partial hashes:
- Signature cache — hashes and dimensions are remembered per file, so re-scanning the same folders is dramatically faster.
- Adaptive timestamp handling — automatically detects and corrects for systematic clock offsets between drives (DST shifts, FAT32 rounding, NAS drift).
- Perceptual image matching — finds resized or re-encoded copies of the same photo, not just byte-identical duplicates.
- Cold-storage manifests — generate SHA-256 checksum manifests of archive drives to verify offline copies later.
- Session save/restore — pause a review and pick it up later.
- Works over the network — local drives, UNC paths (
\\NAS\Share), and mapped drives.
Grab the latest portoMatch-X.Y-win64.zip from Releases,
unzip it anywhere, and run portoMatch.exe. No installer, no admin rights. Your settings,
licence, caches and audit logs live right next to the exe; the only things that go to the
Windows temp folder are the thumbnail cache and the exe's own unpacked runtime.
This build is not code-signed (that costs money we're not spending yet), so Windows
will show "Windows protected your PC" the first time you run it. Click More info →
Run anyway. This is standard for small, independently-published Windows software — it
means Windows hasn't seen this specific file before, not that anything is wrong with it.
Check the .sha256 file next to the zip if you want to verify the download yourself.
Everything below the line is free, no licence needed, no time limit, no nag beyond an occasional reminder. A Pro licence removes that reminder, authorises commercial use, and additionally unlocks:
- Alternate layouts — Gallery + Inspector, Dense List, and Compare-First views (switch anytime under View → Layout; Classic stays free).
- Reconcile Mode — a dual-pane backup audit for verifying an entire mirror/backup copy against its source.
- Partial Match review — a dedicated view for reviewing partial (not exact or visual) matches.
- Signature cache — remembers file signatures across sessions for much faster re-scans of large libraries, and powers Find Rotated Copy, which depends on it.
- Cold Storage Pro — multi-drive manifests, audits, spin-up reminders, and S.M.A.R.T. health checks that keep your cold-storage drives and backups verified, plus cold-storage cross-checks during a compare.
- EXIF editor and the provenance row — see (and edit) which software last touched a file.
- Visual duplicates in the single-folder Duplicate Finder.
- Build Reference Index — pre-index a large reference root for instant lookups on future scans.
- Backup Sync Mode — replays the deletions you made in a folder onto its backup copy, from the audit log, with a full preview before anything is removed.
- Commercial use, and no periodic reminder notice.
Everything else — comparing folders, side-by-side review, deleting/moving with an audit trail, the Rejected workflow, Smart Select, session save/restore, cold-storage manifests (Lite) — is free with no catch.
Buy a Pro licence: [LS purchase link placeholder]
Your licence key is in the purchase receipt e-mail and on Lemon Squeezy's "My Orders"
page (format XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX).
- Download and run portoMatch (above) — the download itself is always free.
- Open Settings → Pro Licence…
- Paste the key and click Activate. The app contacts Lemon Squeezy once to activate this computer, then works completely offline; it re-checks the key quietly about once a week when you happen to be online.
Your key activates on up to 3 computers. To move it to a new machine, open Settings → Pro Licence… on the old one and click Deactivate first.
portoMatch talks to the network for exactly two things, and never on its own without you clicking something. The update prompt can be switched off in Settings; the licence check only happens if you activated a Lemon Squeezy key:
- Update check (about once a month portoMatch asks "Check for updates now?" — nothing is fetched unless you click Check; Help → Check for Updates… always works on demand): fetches one small JSON file listing the latest release from this GitHub repo. Sends only an app-name/version header — nothing about you or your files.
- Pro licence activation and re-validation (only if you've entered a Lemon Squeezy key): sends the key and this machine's name to Lemon Squeezy once to activate, then a short silent re-check about once a week. Nothing about your files or usage.
Nothing else ever leaves your computer. Your files, filenames, and folder paths are never sent anywhere.
This page is the quick tour. For the complete walkthrough — every button, every mode, and the safety model in depth — see README_USER.md.
Open an issue on this repository, or reply to your Lemon Squeezy purchase receipt for licensing questions.
portoMatch by portoWorks.