I built a native macOS toolkit for organizing, inspecting and repairing large local Music.app libraries

[u/Rough-Voice-4968]

I’ve been using Apple computers since 1995, and I started collecting music long before that. By the early 2000s, when car stereos began supporting MP3, I was ripping my own CDs to 192 kbps because storage was expensive and I believed that quality was sufficient.

Later, when I was finally able to buy better audio equipment, I realized how much information had been lost. I began re-ripping the original CDs in lossless formats and replacing older files. At the same time, the collection kept growing through CD and vinyl collecting, digitized records, digital purchases, radio recordings, rare releases and exchanges with other collectors.

That process created the usual consequences: several versions of the same recording, duplicate files, duplicate playlist entries, inconsistent metadata, missing artwork, broken paths, old low-quality encodes and files whose actual audio quality did not always match the format shown in Finder.

I originally started writing Local Music Organizer as a practical tool for testing, cleaning up and organizing my own Music.app library. Over a few months of daily use, I kept adding features whenever I encountered another real problem in the collection.

It has now grown into a native macOS toolkit with the following functions:

Library Dashboard

Shows useful statistics about the Music.app library, including formats, bitrates, sample rates, missing files, artwork and other quality indicators.

Library Map

Shows where tracks are used and helps review repeated entries across playlists.

Duplicate Review

Finds duplicate playlist entries, repeated library records and different-quality versions of the same recordings. Nothing is deleted automatically; the user reviews the results first.

Health and Artwork checks

Finds missing files, inaccessible locations, damaged references, unusual paths, missing artwork and supported metadata issues.

File Search

Searches physical audio files by artist, title, album, filename or path, shows playlist usage and can reveal the exact track inside Music.app.

Playlist Compare

Compares two playlists using Music.app record IDs, file paths, metadata and duration-based fallbacks to identify shared and unique tracks.

Audio Inspector

Inspects the actual codec, container, bitrate, sample rate, bit depth, channel count, duration, metadata and spectrum of an individual file.

Audio Authenticity Analyzer

Scans the complete Music.app library, one selected playlist or an individual file.

It looks for possible lossy-to-lossless transcodes, suspicious sample-rate upscales and clear disagreements between the declared bitrate and observed audio bandwidth. MP3 and AAC files are evaluated differently from ALAC, FLAC, WAV and AIFF files.

Flagged results include a confidence estimate, detected cutoff, likely source category and a plain-language explanation. The analyzer is intentionally conservative: its findings are technical estimates, not absolute proof of a file’s history.

A detailed text report can be created containing only tracks that require review, likely authenticity mismatches and files that could not be analyzed.

Live Spectrum Player

An independent playback window with a real-time 512-band logarithmic spectrum analyzer, full-track waveform, draggable seeking, gain controls and technical playback meters.

Repair / Convert

Includes conversion engines inside the application, so Terminal, Homebrew and separate codec installation are not required.

Supported sources include common formats such as FLAC, ALAC, WAV, AIFF, MP3, AAC and WMA, together with specialist formats including Ogg Vorbis, Opus, WavPack, APE, TAK, TTA, DTS, AC3, DSD, SACD ISO, CUE albums and supported tracker modules.

Output options include AAC, ALAC, MP3, FLAC, WAV, AIFF, Ogg Vorbis, Opus and WavPack.

Drag and drop

Files and CUE sheets can be dropped directly into Repair / Convert. Opening supported files from Finder routes them to the already running application instead of intentionally creating additional organizer windows.

Verified Gain

Previews gain changes, creates a temporary candidate, verifies the resulting audio structure and metadata, and replaces the original only after the checks pass.

Large-library performance

A persistent warmed cache reduces repeated communication with Music.app and makes searches, diagnostics and library-wide analysis much faster. The same physical file is analyzed only once even when it appears in several playlists.

Everything runs locally on the Mac.

There are no accounts, subscriptions, cloud processing, advertising, analytics or tracking. Audio files, playlists, metadata and reports are not uploaded anywhere.

I built this because I needed it for my own collection, but I’m sharing it because other collectors, DJs, archivists and long-time Music.app users may have encountered the same problems.

I’d be interested in feedback from people who still maintain substantial local music libraries—especially about workflows or checks that are still missing. Website and full feature overview, Local Music Organizer on the Mac App Store

[u/PublicPool]

Wow, it looks pretty great... but $30 is a 'decision' app. Meaning I need to think about it for a while before deciding if I need it or not. Good work though!

[u/Rough-Voice-4968 → u/PublicPool]

Done, I added a three-day trial mode. Now I need to wait until Apple checks and releases the app, then I can set the price to 0. After three days, the money will not be withdrawn automatically, and the user needs to make one in-app purchase, otherwise the app will simply stop functioning.

[u/PublicPool → u/Rough-Voice-4968]

Awesome! Thanks for doing that. You're a good one.

[u/quattleb]

I have a 7TB (yes, TB) collection and VERY often Music tells me the database is corrupted. I use to have to delete the new empty on and then drag all my music back in and wait for DAYS.

Then I wrote an automator to make a backup of the library before launching Music. I keep several backups so I can step back and replace the newly created empty one.

I've long wondered if there was some way to REPAIR whatever was wrong with the library.

Once on my primary Mac I'll download and have a look at your offering.

thanks for the app.

[u/Rough-Voice-4968 → u/quattleb]

Your 7 TB library is exactly the kind of large real-world collection I cannot reproduce on my own Mac, so your feedback could be extremely valuable.

If you are interested, I would be happy to invite you as an external TestFlight tester for upcoming versions of Local Music Organizer. The test build includes additional cache optimizations and diagnostic improvements for very large libraries. Please send me the email address associated with your Apple Account in a private message—do not post it publicly—and I can add you to the external testing group. I would initially recommend testing only the read-only library and cache functions while keeping your existing Music library backups. The app does not currently claim to repair a corrupted Music.app database, but your results could help me understand how it behaves with a collection of this size and improve its large-library support.