r/osx • u/Hour-Offer-6942 • 5d ago

Free, open-source Mac app that shows what is filling your disk in seconds

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Gallery image

Gallery image

I made Hollow, a disk usage map for Apple silicon Macs (macOS 14+). It draws every file as a rectangle sized by the space it takes on disk, so the big things are obvious right away. My home folder (1.5M files, 202 GB) scans in 5.2 seconds on a MacBook Air M5.

A few ways I use it:

  • Zoom into ~/Library to see which app's caches grew.
  • Filter by file type, minimum size or age to find old videos.
  • Move to Trash from inside the app. Undo works and sizes update without a rescan.

Privacy: it reads only names, sizes and dates, uses no network, and does not download iCloud files while scanning.

Caveats: it is not notarized because I don't have a paid developer account yet. On first launch, right-click the app and choose Open, or use System Settings > Privacy & Security > Open Anyway. Give it Full Disk Access if you want it to see Mail, Messages and Safari data. Otherwise those folders show as unreadable.

Free, MIT license: https://github.com/yukij3/hollow/releases/latest

It is v0.1.1, so bug reports on GitHub are welcome.

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3

u/porkchop_d_clown 5d ago

How is Hollow different from Grand Perspective? I mean, it looks almost the same, and Grand Perspective and that's open source as well.

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u/Hour-Offer-6942 5d ago

Fair question. The look is on purpose: I like GrandPerspective's cushion treemap and kept it. The main difference is speed. Hollow reads folders in parallel, one thread per core. On my M5 Air the GrandPerspective 3.8.1 app took 6.69 s on /Applications and Hollow took 1.67 s; on /System/Library it was 8.99 s vs 1.56 s. My home folder (1.5M files) scans in about 5 s. It also picks up file changes live without a full rescan, and Move to Trash has Undo. If GrandPerspective is fast enough on your disk, there's no strong reason to switch.

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u/porkchop_d_clown 5d ago

Fair enough. I have noticed Grand Perspective has gotten slow. I'll take a look!

1

u/porkchop_d_clown 5d ago

You may need to include instructions on how to run unsigned software on a Mac, though.

1

u/Hour-Offer-6942 5d ago

Thanks! It's in the README: right-click > Open the first time. Notarizing it is on my list.

1

u/Hour-Offer-6942 5d ago

I'd happily notarize it, but that needs a paid Apple Developer account and I haven't budgeted for one yet. It's a side project I put together over a couple of evenings because the disk tools I tried were too slow at scanning and finding big files.

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u/distreszed 5d ago

Grand Perspective rip off 100%

2

u/paul_h 5d ago

Akshully, Disk Inventory X came first, with its initial release on March 7, 2004, while GrandPerspective with the same visualization followed with its first release on September 20, 2005.

0

u/Hour-Offer-6942 5d ago

Ha, lots of disk tools draw a treemap, and they're still different apps. Where Hollow differs is speed: on my M5 Air, GrandPerspective 3.8.1 takes 6.69 s on /Applications and Hollow takes 1.67 s. On /System/Library it's 8.99 s vs 1.56 s. Try both on your own disk and see which one you'd rather wait for.

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u/Biliunas 4d ago

I recommend using disk inventory X!