Guides

Practical, tested guides to macOS storage.

Everything here comes from a real cleanup that took one 512 GB MacBook Pro from 20 GB free to 215 GB free. Commands are tested, numbers are measured.

• Why is System Data so large on your Mac?

  System Data is not one thing. It is every file macOS cannot file elsewhere. Here is what is actually inside it, with the real sizes found on a 512 GB MacBook Pro.

• How to clear System Data on a Mac without breaking anything

  A step-by-step guide to safely reclaiming System Data on macOS, with the exact Terminal commands, what each one does, and which things you must never delete.

• Free CleanMyMac alternatives in 2026, compared honestly

  CleanMyMac costs money and does things some people would rather it did not. Here are the free alternatives that actually work, what each is good at, and where each falls short.

• Docker.raw is taking up hundreds of GB on your Mac — here is why

  Docker.raw can report 494 GB while occupying 9 GB, or quietly consume 300 GB of real disk. Sparse files explain both, and here is how to measure and reclaim it correctly.

• How to find what is taking up space on your Mac using Terminal

  The du, df and mdfind commands that actually work on macOS, including the common mistake that silently hides tens of gigabytes of hidden folders.

• What is purgeable space on a Mac, and can you actually free it?

  Purgeable space is disk macOS has promised itself it can reclaim on demand. No third-party cleaner can free it directly. Here is what it really contains and what genuinely moves it.

• Is it safe to delete ~/Library/Caches? Mostly yes, and mostly pointless

  Emptying ~/Library/Caches is the most repeated Mac advice and one of the least effective. Here is why the gigabytes are almost never in Caches, and which neighbouring folders actually hold them.

• WhatsApp and Messages media: the 92 GB hiding in Group Containers

  Messaging apps store every photo and video you have ever received inside Group Containers, where Finder will not show it and no macOS setting will prune it.

• node_modules and build output: the 66 GB most developers never look at

  Dependency folders and stale build caches accumulate across every project you have ever cloned. Here is how to measure them and the one deletion that quietly breaks a library.

• Xcode leftovers: DerivedData, simulators and runtimes you can safely remove

  Xcode keeps build indexes, simulator devices and installed runtimes long after you need them, and some survive uninstalling Xcode entirely.

• Git repositories are taking up space. Repack them, do not delete them

  A .git directory can reach several gigabytes, and it is the one folder on a developer machine that is genuinely irreplaceable. Here is how to shrink one safely.