If your Mac's storage jumped by tens of gigabytes shortly after installing GarageBand or Logic Pro, and you never actually recorded anything, the cause is almost certainly sound content, not your own work. Both apps rely on large shared libraries of instrument samples, Apple Loops, and effect impulse responses that install separately from the application bundle itself, generally under system-wide locations like /Library/Application Support/Logic and /Library/Audio/Apple Loops. GarageBand shares much of this content with Logic Pro, since Logic is effectively GarageBand's professional superset built on the same instrument and loop foundation. None of it is optional in the sense of the app refusing to work without it, but a lot of it is optional in the sense that you can choose which packs to keep installed — and most people never touch that choice.

Where the shared sound content actually lives

Unlike your projects, which live wherever you saved them, the instrument samples and loops that GarageBand and Logic play back are stored centrally so both apps — and any future project — can reuse the same files rather than each project carrying its own copy. The general locations are system-wide rather than per-user: /Library/Application Support/Logic holds much of the instrument and library data, and /Library/Audio/Apple Loops holds the loop content used by both apps' loop browsers. You can check how much space either location is using with a simple measurement:

du -sh "/Library/Application Support/Logic"
du -sh "/Library/Audio/Apple Loops"

This tells you the scale of what is installed without requiring you to open either folder or identify individual files.

Two apps, one shared library

It is worth understanding why GarageBand alone can pull in so much content. Apple built Logic Pro as a superset of GarageBand — the same core instruments, the same Apple Loops format, the same underlying audio engine — with Logic adding professional mixing, scoring, and production features on top. Because of that shared lineage, installing either app can trigger downloads of content the other app also uses. If you have both installed, you are very likely sharing a large portion of the same sample library rather than storing two separate copies.

How the content gets onto your disk in the first place

There are two moments where this download happens. The first is on initial launch, when both apps typically prompt you to install a "core content" package before you can do much meaningful work — this is a reasonable, expected download and usually a few gigabytes. The second is ongoing: each app has a Sound Library section in its preferences where you can browse and download additional instrument and loop packs at any time, well after the initial setup. Downloads triggered from either point land in the same shared locations described above.

How large this can get

The core content prompt on first launch is modest by comparison to what is available. Logic Pro's full catalogue of optional content — every instrument expansion, every genre-specific loop pack, every additional set of impulse responses for reverb — is large, and downloading everything on offer can easily run to tens of gigabytes. Most users will never need all of it; a person working primarily with a handful of instruments and a couple of genres is using a small fraction of what the full library contains.

Manage it through the Sound Library manager, not Finder

The correct way to add or remove this content is through each app's own manager: GarageBand > Preferences (or Settings) > Sound Library, or Logic Pro > Sound Library > Manage Sound Library. Both present a checklist of packs, organised by instrument or genre, with a clear indication of what is installed and what is available to download. Removing a pack from here is a deliberate, tracked operation.

Deleting files directly out of /Library/Application Support/Logic is not the equivalent shortcut it might look like. Both apps expect specific packs to be present or absent consistently with an internal manifest of what should be installed. Remove files by hand and you risk a mismatch between what the manifest thinks exists and what is actually on disk — which can surface later as missing instrument sounds, patches that fail to load, or the app repeatedly prompting you to reinstall content it thinks is missing. The Sound Library manager exists specifically so this bookkeeping stays correct.

What's safe to remove if you use only a handful of instruments

If you know your own workflow — say, you only ever compose with a piano, a couple of synth patches, and a drum kit — you can go into the Sound Library manager and remove packs for instruments and genres you never touch: entire orchestral sections, world instrument collections, or genre-specific loop packs you have never opened. This is genuinely safe. Nothing about removing shared sample content threatens any project you have already created, because your own recordings, MIDI data, and mix settings are stored inside your project files, not inside the shared library. The only thing you lose access to is the ability to add new instances of that particular instrument or loop pack until you reinstall it — and reinstalling is always available from the same manager, at any time, at no cost beyond the download itself.

Conclusion / VolumeLens tie-in

Shared content libraries are one of the more forgivable ways a Mac fills up: the space is doing real work, just not necessarily work you personally asked for. The fix isn't deleting blindly — it's going into the tool that manages the content and removing only the parts you have genuinely never used, which Logic and GarageBand both make possible without any risk to your own projects.

We built VolumeLens because we needed a way to see how much space a library like this was actually using relative to everything else on a Mac, before deciding whether it was worth touching at all. It scans locations like /Library/Application Support and shows you the real size of what's there, so you know whether trimming Logic's sound content is worth ten minutes of your time or not worth bothering with. Our pricing page has details if you want the full breakdown of what's installed and where.