Before the Trash
No broken playlists
Every playlist and crate that uses a duplicate is moved to the copy you keep first. Then the duplicate goes to the Trash, where you can still get it back.
Finds every copy of the same recording by sound, then keeps your Rekordbox, Serato and VirtualDJ playlists pointing at the copy you keep. Pro is $39 once.
Similarity is a well-known duplicate finder that compares audio by content and by tags, and it handles images too. It works on files and has no link to your DJ software, so when a duplicate is removed, the playlists and crates that used it show a missing track. Its Mac version was last updated in October 2020 (2.4.4) and runs on Apple Silicon through Rosetta; the Windows version was last updated in November 2021 (2.5.1). If your library lives inside Rekordbox, Serato or VirtualDJ, finding the duplicates is only half the job.
Supported today
Rekordbox · Serato DJ · VirtualDJ (incl. Favorite Folders) on Windows 10+ and macOS (Apple Silicon + Intel). No DJ software? Folder Library mode audits plain music folders too.
What each app does when you ask it to clean up a DJ library.
| What you need | Music Library Doctor | Similarity 2.4.4 |
|---|---|---|
| Keeps your sets workingPlaylists and crates follow the copy you keep | Rekordbox, Serato and VirtualDJ | Works on files only |
| Built for today's MacsRuns natively on Apple Silicon | Native, updated regularly | Mac: Intel build via Rosetta, last updated October 2020 (Windows: November 2021) |
| First scan speedSame Mac mini, same morning | About 392 files a minute | 85–126 files a minute |
| Intro edits stay apartAn intro edit is a version, not a copy | A longer intro is not called the same recording; Clean/Dirty edits and mashups wait in review | Content and tag scores you tune by hand |
| Borderline matchesWhat happens when it is not sure | Set aside in their own list for you to review | Marked by the thresholds you choose |
| Three ways to matchPick the strictness you trust | Identical file, artist + title + length, or by sound | By sound and by tags |
| Staying up to dateWhat updates cost after you buy | Every future update included | $9.95 for each year of updates after the first |
In our own test on a Mac mini (Apple M4) on 25 September 2026, MLD fingerprinted 2,472 tracks (26 GB) in 378 seconds, about 392 a minute. Similarity 2.4.4 processed 5,073 files in the first 40 minutes of a scan of the same drive, between 85 and 126 a minute.
The folders were not the same and both apps shared the machine, so treat the roughly threefold difference as approximate. After the first scan MLD reuses saved fingerprints, and a rescan takes seconds.
Similarity: Premium is sold as a licence plus an update period: $19.95 with one year of updates or $29.95 with three, and $9.95 for every further year of updates. Staying current for three years costs about $40. It also finds duplicate images, and includes a tag editor, a spectrum analyzer and a sonogram view.
Music Library Doctor: the free tier finds and shows every duplicate. Pro is $39 once with every future update included, or $9.99 a month: duplicate removal with playlists kept, missing-track repair, fake-320 and fake-FLAC detection, playlist conversion between DJ apps and Track Matcher.
The short version: if you want one tool for duplicate audio and image files, and your music does not live in DJ software, Similarity covers that. If your library lives in Rekordbox, Serato or VirtualDJ, MLD removes duplicates without breaking your sets.
As of September 2026, from Similarity's own website. Prices change; check theirs before you decide.
A duplicate finder deletes files. A DJ library also has sets, cue points and crates built on those files.
Before the Trash
Every playlist and crate that uses a duplicate is moved to the copy you keep first. Then the duplicate goes to the Trash, where you can still get it back.
By ear
A 320 kbps MP3, a lower-bitrate re-encode and a FLAC of the same recording are grouped together, even when the file names and tags say otherwise.
On evidence
Each copy shows its bitrate, length, size and a quality score read from the audio, so an upscaled "320" does not win over a real one.
Your call
You review duplicates group by group. Anything the app is not sure about waits in its own list.
The difference is what happens after a duplicate is found. MLD reads and writes Rekordbox (including the encrypted 6+ database), Serato crates and VirtualDJ's database directly, so removing a copy never leaves a hole in a set. Fingerprints are saved, so after the first scan a rescan takes seconds, and a fingerprint is only taken again when its file changes. An intro edit that starts well before the original is kept apart on purpose: it is a version you may want, not a copy.
Both compare the sound, not just the name. The simplest way to know for your library: run MLD's free version and compare its groups with Similarity's. The free tier finds and shows every duplicate.
Not with MLD. Before a duplicate goes to the Trash, every playlist and crate that uses it is pointed at the copy you keep, and every DJ database is backed up before it is written.
It is still matched. MLD lines the two copies up by sound, so a copy that starts up to about two seconds later is found as the same recording. A longer difference usually means an intro edit, and those are kept apart on purpose.
Yes. MLD runs natively on Apple Silicon and Intel Macs (macOS 10.15+) and on Windows 10/11.
No. MLD is built for music libraries. If you also need to clean up duplicate photos, Similarity or a photo tool covers that.
Only if you want one. Pro is $39 once, or $9.99 a month if you only need it for a job.
Yes. The free version finds and shows every duplicate, along with the Library Health Score. Removing duplicates needs Pro.
Free tier covers scanning and detection. Pro is a one-time lifetime license, or a monthly plan if you prefer. Current pricing is on the homepage.
It finds Rekordbox, Serato and VirtualDJ on its own, and reads plain music folders when you use none of them. Nothing to configure before the first scan.
macOS 10.15+ or Windows 10+. Notarized and code-signed. See pricing