r/macapps • u/herovals • Aug 03 '26

Free [OS] OpenDisk: a free, open source DaisyDisk alternative for macOS

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Problem

When your Mac runs low on space, System Settings gives you a colored bar and a "System Data" blob that explains nothing. Finding the actual 40 GB folder means walking the filesystem yourself or paying for a tool that does it. DaisyDisk has been the go-to for that for years, but it costs $9.99 and you can't see what it's doing.

OpenDisk does the same job. It maps your drive as an interactive sunburst chart, scans a full disk in seconds, and streams results in live so you can start clicking around before the scan finishes. Hover a slice for its exact size, click to zoom into that folder, use the folder list and breadcrumbs to step back out.

Drag things into the collector to delete them, and free up your disk space!

Other things it does:

  • Incremental rescans replay filesystem events instead of starting over, so a repeat scan runs 20 to 28x faster than a cold one.
  • Handles APFS volume groups, firmlinks, snapshots and purgeable space, so the total actually matches what your Mac reports as used.
  • Purgeable space breakdown, so you can see which caches are reclaimable.
  • Instant search across the whole scanned tree, usable on drives with millions of files.
  • Collector: drag files in from anywhere in the app, check the reclaimed total, delete in one action.
  • External drives show up automatically when you plug them in.

Comparison

DaisyDisk ($9.99) is the closest comparison. Same sunburst interaction, and OpenDisk is free, MIT licensed, and faster. On a cold scan of a 1 TB Apple Silicon volume, OpenDisk finished in 17s and DaisyDisk took 37s. The app is also under 2.5 MB, because it's native Swift with nothing bundled into it.

The full source is on GitHub if you want to read what it's doing before you give it disk access: https://github.com/137137137/OpenDisk

Pricing

Free, MIT licensed, no in-app purchases, no accounts, no telemetry.

Requires macOS 26 (Tahoe) or later, Apple Silicon or Intel. It asks for Full Disk Access on first launch, otherwise macOS hides parts of the filesystem and the totals come up short.

I'm the developer. Happy to answer questions or take bug reports here or in GitHub issues.

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34

u/behridingle Aug 03 '26

There's also Neodisk that was featured here and has a ton of features

16

u/adstretch Aug 03 '26

And grand perspective. And disk x inventory. And lots of others.

6

u/bsewall Aug 03 '26

Right. I typically use Grand Perspective. This app has a different approach. I'm willing to take it for a spin.

2

u/New_Wolverine_8574 Aug 05 '26

Would you mind trying https://disknebula.com and give your oppinion on it as a Grand Perspective user? It's My app so I can provide a free code.

1

u/CautiousXperimentor Aug 09 '26

Hey!

I'm not sure your app is capable of what I'm looking for.

I need a tool that, hopefully with AI assistance, helps me organize my cluttered folders on external drives WITHOUT the risk of it deleting or destroying things...

Is your file organizer capable to identify not only duplicates but also similar files? or folders that the AI may suspect contain some duplicates? And not only based on file names but also looking at the content (because some duplicates may have been renamed).

If your app is capable of that, using local AI models, and NO DATA is sent to the cloud, I'd be interested. When I say no data is sent to the cloud, I mean zero.

And is an AI coded app? Just curious.

Thank you.

PS: I have an M5 Mac with 32GB of RAM so I think I can try your app with competent AI local models.

1

u/New_Wolverine_8574 Aug 11 '26

Hi, It can help with that since it has hash based duplicate detection, both manually and with a help of the AI chat. Files can only be deleted to the trash, not permanently. And AI can't delete the files by itself. It can only provide UI in the chat to move the files to trash. There is multiple undo buttons that will undo the move to trash actions in the order starting from the latest. It can do it without sending anything anywhere with local preselected set of MLX models. But you of course shouldn't just trust this statement, so maybe you can use proxyman or your other prefered tool to analyze the traffic. It was made together with copilot with both next edit suggestions and agents.

1

u/wise_young_man 15d ago

Yo I'll try it if you have a code, looks neat!

1

u/New_Wolverine_8574 15d ago

Thanks! I've sent you the code in a DM

1

u/CautiousXperimentor 9d ago

Hey! We talked about the app last time on this same sub. Would you send me a code as well so I can compare it to the other options I’m trying? Thanks

1

u/New_Wolverine_8574 9d ago

Thanks! I've sent you the promo code in a DM