On a developer's Mac, most of the space usually sits in a few folders that build tools, simulators, containers, AI models and backups fill. Here they are as Wombit explains them, each in the words of its open catalog: how safe it is to remove, what it is, where it lives and how the app removes it.
The usual places
- Safe
Xcode DerivedData
Build products, indexes and logs Xcode keeps for every project you've built.
~/Library/ Developer/ Xcode/ DerivedDataMoves it to the Trash - Usually safe
Simulator devices
The simulated devices you run apps on from Xcode, each with its own installed apps, data and settings.
~/Library/ Developer/ CoreSimulator/ DevicesExplained only: the app shows you how - Usually safe
Docker Desktop disk image (Docker.raw)
The virtual disk where Docker Desktop keeps all your images, containers, volumes and build cache.
~/Library/ Containers/ com.docker.docker/ Data/ vms/ 0/ data/ Docker.rawRuns Docker's own build cache cleanup, never deletes Docker.raw - Usually safe
node_modules
A JavaScript project's installed dependencies, which its package manager can install again.
~/projects/ storefront/ node_modulesMoves it to the Trash - Review first
Ollama models
Language models you've pulled or created with Ollama, stored as shared layers.
~/.ollama/ modelsExplained only: never removed - Review first
iPhone and iPad backups
Backups of an iPhone, iPad or iPod touch that were made on this Mac, one folder for each device.
~/Library/ Application Support/ MobileSync/ Backup/ *Moves it to the Trash - Managed by macOS
Time Machine local snapshots
Hourly snapshots of your startup disk that Time Machine keeps on the disk itself, so you can restore files even without your backup disk.
com.apple.TimeMachine.2026-09-27-101512.localRuns tmutil deletelocalsnapshots, for Time Machine's own snapshots - Managed by macOS
Apple Intelligence models
The on-device language and image models that Apple Intelligence features use.
/System/ Library/ AssetsV2/ com_apple_MobileAsset_UAF_FM_*Never removed. The app shows the setting that turns the feature off
How the app finds them
A scan measures every folder, then each one is matched against the catalog's rules. A match brings the rule's explanation, its safety level and how to remove it; a folder no rule explains says so, and stays where it is. On the map, Safe to Remove lights up only the items whose owner recreates them by itself.
Each rule has its own page under Safe to delete?, with the sources it was checked against. For the biggest ones, the guides go further: Xcode, Docker.raw, node_modules, local AI models and iPhone backups.