Renamed, moved or re-tagged — still recognized. Music Library Doctor knows each track by what it sounds like, not by what it is called.
Your DJ software knows a track by its file name and folder. Rename the file, move it to a new drive or let a tag editor tidy it up, and the track turns red: the software looks in the old place, under the old name, and finds nothing.
The relocate tools built into DJ apps help only as long as the name is unchanged. Point them at a folder and they look for the same file name. A file that was renamed, or kept in another format — the MP3 you lost, still on your drive as an M4A — is never matched, so it is searched for by hand, one track at a time.
Names and tags change all the time. The sound of a track does not.
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.
A renamed file. "03 - Track.mp3" that became "Artist - Title (Extended Mix).mp3" holds the same sound, so it is found under its new name.
A moved file. A track copied to a new drive or a new folder is recognized where it is now, not where your DJ app last saw it.
A re-tagged file. Tag editors change the artist, title, artwork and comments — not the audio. The seal stays the same.
Another format. A track kept as an M4A after the MP3 went missing has a different file, but the same recording. The app compares how the two sound and suggests that copy.
A hash is a short fingerprint of data: the same input always gives the same result, and changing a single byte changes the result completely. Music Library Doctor computes it over the audio only, leaving out everything a tag editor touches, so the seal follows the music and nothing else.
It all happens on your computer. Your music, its seals and your library never leave it.
The seal is kept for every track the app has listened to, so a track that was heard before it went missing can be found by its sound later — under any name, on any of your drives. Fix Track and the missing-tracks list both use it, next to the name search, and every suggestion still waits for your confirmation. Rekordbox, Serato and VirtualDJ are updated directly, without an XML round-trip, so the repaired track keeps its playlists, crates and cue points.
It is how Music Library Doctor recognizes a track by its sound. The app listens to each track once and keeps a SHA-256 hash of the audio itself, leaving out the file name, the tags and the folder. Rename, re-tag or move the file and its seal stays the same, so the track is still recognized.
Yes, when the app heard the track before it went missing. The seal of the lost track is looked for on your disks, and a file with the same sound is suggested whatever it is now called. A copy kept in another format, such as an M4A of a lost MP3, is recognized by how it sounds. You confirm each match before it is re-pointed.
No. Listening, sealing and matching all run on your computer. This is separate from Sound Recognition, which names an unknown file by asking an online service.
The app listens in the background at low priority and pauses while you clean up duplicates, gather your library or repair a file.
Rekordbox (including the encrypted Rekordbox 6 and 7 library), Serato (including Serato 4 and 5) and VirtualDJ, on macOS and Windows.
Finding missing tracks and duplicates is free, and every problem is counted. Repairing missing tracks in bulk and cleaning up duplicates are part of 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
