Your drive fills up with copies you never meant to keep — the same photo saved to three folders, downloads grabbed twice, backups that doubled everything, and "file (1), file (2)" clutter scattered everywhere. DupeDoctor finds them all and helps you reclaim that space safely. It's a fast, local-first duplicate file finder and disk-space reclaimer built for Windows 11, and it runs 100% offline. Point DupeDoctor at any folders you choose and it scans them in a single pass. Exact duplicates are confirmed by content, not just by name or size: a quick size grouping prunes the obvious non-matches, then a fast BLAKE3 hash verifies true byte-for-byte copies, so renamed files are still caught and there are no false positives. Progress streams live with a real phase stepper and an honest progress bar, and you can cancel any time and keep the partial results. DupeDoctor goes well beyond exact copies. It finds look-alike photos using perceptual hashing, catching the same image at different resolutions, crops, or re-encodes (JPEG vs PNG, web exports vs originals) that byte-matching misses — with a similarity slider you can tighten or loosen, and an option to match rotated and flipped shots. It groups copy-named files (the "file (1)" convention) in the same folder. It detects similar videos by sampling and fingerprinting frames, so re-encodes, resizes, and format changes are recognized. It groups duplicate songs that share the same track across different bitrates or formats. And it surfaces your biggest space hogs, files you haven't touched in months or years, installer and archive leftovers (.exe, .msi, .zip, .iso), and empty folders — all from one scan. Results are built for confident decisions. Duplicate sets are color-coded and shown with image thumbnails, per-file paths and dates, and a per-set reclaimable amount, all in a virtualized list that stays smooth even with huge result counts. Open a side-by-side compare to review look-alike photos before you decide. One-click auto-keep rules (keep newest, oldest, or shortest path) pre-select the redundant copies in exact and copy-named sets, with a running reclaimable meter, undo, and clear. Filter by path, sort by size, date, or location, and set a minimum size to focus on what matters. Safety is the whole point of a duplicate finder, so it's enforced in code, not just the interface. Deletion always goes to the Windows Recycle Bin — there is no permanent-delete path — so anything you remove is recoverable in one click. At least one file in every duplicate set is always kept; the app will not let you empty a group, and the backend re-validates every request. Look-alike photos, videos, and songs are never auto-selected, because similar is not identical — those always require your deliberate review. Windows system locations are protected and never touched. After a cleanup, only files that actually recycled leave the view; anything that failed stays visible with its reason. When deleting isn't what you want, DupeDoctor offers alternatives. Move selected extras to a folder of your choice instead of recycling them. On exact-duplicate sets, replace redundant copies with hardlinks to reclaim the space while keeping a file in every location. Export a full report of everything found as CSV or JSON for your records or your own review. A light automation layer keeps things tidy without running a background service. Add watched folders (like Downloads), and DupeDoctor can quietly re-check them when you open the app and show a banner when there's space to reclaim. A persistent scan cache remembers hashes for unchanged files so repeat scans are faster. An optional system tray, native notifications, an auto-keep rule, and a run-on-login mode (starting minimized to the tray) round it out — all optional, all under your control. DupeDoctor is designed to be a premium, calm tool to use: a warm light theme with a first-class dark variant, clear typography, and motion that always respects your reduced-motion and transparency settings. Privacy is structural, not a promise. There is no network client, no telemetry, no account, and no cloud — open a network monitor and you'll see no connections. Everything happens on your machine. DupeDoctor is a one-time purchase: no subscription, no ads, no upsells. Buy it once, own it, and reclaim your disk space with confidence.