If you've used a Mac since the iTunes era, there's a decent chance a large chunk of disk space is sitting in ~/Music/Music/Media, which is where the Music app — iTunes's successor — stores your actual audio and video files by default. Libraries that migrated forward from an older iTunes setup and haven't been fully reorganised may still have media under a legacy ~/Music/iTunes layout as well, sometimes both at once. If you're an Apple Music subscriber, there's a setting called Optimise Storage that can trim this automatically. But it only helps with part of the problem, and understanding which part is the difference between a safe cleanup and quietly losing music you can't get back.

Where the Music app actually stores files

By default, the Music app keeps your media library under ~/Music/Music/Media. If your library goes back to the iTunes days and was carried forward through several macOS and app upgrades without a full reorganisation, you may also find a ~/Music/iTunes folder still holding older content in the legacy layout. Both are real media storage, not caches — the files there are your actual songs, downloaded videos, and imported audio, not something the system can silently regenerate.

You can check the overall size of your library the same way you'd check any folder:

du -sh ~/Music/Music/Media
du -sh ~/Music/iTunes 2>/dev/null

For anyone who has been ripping CDs, buying tracks, or importing audio files since the 2000s, it is common for this combined total to run into tens of gigabytes, especially if the collection includes lossless or high-bitrate files, which take up considerably more space per track than a compressed download.

What Optimise Storage does

If you subscribe to Apple Music, there's a setting — found under Music's preferences, in a General or Files section depending on your macOS version — usually labelled Optimise Storage. When enabled, it automatically removes the local copy of downloaded songs you haven't played in a while, while keeping them visible and available in your library so you can stream them again or re-download them on demand.

This works well specifically because Apple Music maintains its own cloud copy of anything that's part of the subscription catalogue and that you've added to your library through it. Removing the local file doesn't lose anything — it just frees the disk space and re-fetches the audio the next time you want to play it, assuming you have a network connection at that point.

Where Optimise Storage stops helping

The setting's usefulness depends entirely on whether a given piece of music is actually in Apple Music's catalogue and was downloaded through the subscription, versus being a file you sourced yourself. Two categories of local file specifically fall outside what Optimise Storage can safely remove and restore:

  • Ripped CDs and other locally imported audio — anything you brought into your library from a personal source rather than downloading through Apple Music. There is no cloud copy of these tracks for the system to fall back on.
  • Purchased downloads or lossless imports that predate or sit outside your current subscription — files that exist on your disk as their only copy, even if they show up in the same library view as streamed tracks.

For files in either category, Optimise Storage either leaves them alone or, in some configurations, may not apply at all, precisely because macOS and the Music app have no way to fetch them again once removed. If you were to delete these manually expecting the same safety net as a subscription download, you would be deleting your only copy of that music, permanently, with no server-side backup to restore from.

A safe approach to a large local library

Before relying on Optimise Storage or removing anything manually, it's worth being clear-eyed about which parts of your library are replaceable and which aren't:

  • Anything downloaded through an active Apple Music subscription is effectively cached — safe to let Optimise Storage manage, since it can be re-downloaded.
  • Anything you ripped, imported, or purchased outside the subscription — including older iTunes Store purchases if you've since cancelled a subscription tied to them, or CDs ripped a decade ago — exists only on your disk unless you've separately backed it up.

If you have a large local collection in the second category and space is genuinely tight, the honest options are to back it up elsewhere (an external drive, a NAS, cloud storage you control) before removing anything, or to accept that it's part of your library's real footprint rather than something a storage setting can quietly reclaim for you.

Why this catches longtime Mac users specifically

This is less of an issue for someone who started using Apple Music from day one and has never manually imported a file. It's much more common for people who've owned a Mac since the iTunes era: a decade or more of ripped CDs, early digital purchases, and imported files sitting alongside a newer Apple Music subscription in the same library, with no visual distinction in the Music app between "this is cached and replaceable" and "this is your only copy." The app doesn't clearly flag the difference, so the safest habit is simply knowing which of your music predates your subscription or was sourced independently, and treating that portion with the same care you'd give any irreplaceable file.

Conclusion / VolumeLens tie-in

A large Music library is one of the more sympathetic reasons a Mac fills up — it usually represents years of a real, personal collection rather than clutter. Optimise Storage is a genuinely useful tool for the part of that library Apple Music can re-fetch on demand, but it was never designed to protect files it has no way to restore, and it's on you to know which of your tracks fall into that category before assuming a setting has your back.

That distinction — between space that's safely reclaimable and space that isn't — is exactly the judgment call we built VolumeLens to support rather than make for you. It shows you where your storage is actually going, including large folders like your Music library, without deleting anything on its own: the only action it ever takes is moving something to the Trash after you've reviewed exactly what's in it, so you're always the one deciding what's disposable and what isn't. You can see pricing and what's included if you want the fuller picture of how it handles cases like this one.