A Mac app, in a window or in the menu bar, that shows what is really inside macOS "System Data" and lets you delete it, item by item.
macos-sysdata.yigitech.dev

Open System Settings > General > Storage on a developer Mac and "System Data" is often the largest line, with no way to see inside it. Finder puts everything it cannot attribute to an app, photos or documents in that bucket: simulator runtimes, Xcode symbol caches, package-manager stores, virtual machine disks, the unified log, per-app data folders.

This app opens the bucket. It is not a cache cleaner: ~/Library/Caches is one small line among fifty, and the app never deletes anything you did not click.

Every release is listed in CHANGELOG.md, including the two that shipped a broken updater and what to do if you are on one of them. There is a short tour at macos-sysdata.yigitech.dev, and contributions are described in CONTRIBUTING.md.

Up to 1.0.4 the app was called SysDataMenu. The bundle identifier, the Homebrew cask and the command-line binary kept their names, so Full Disk Access, your settings and any scripts carry over without reinstalling.

brew install --cask Jarvis322/tap/sysdata

Or download the disk image, open it and drag the app onto Applications. Every release carries the same image as SysDataMenu-<version>.dmg. A .zip of the same app is attached to every release for anyone scripting the download.

If the app is already in Applications from the disk image, brew install stops with "It seems there is already an App". Hand the existing copy to Homebrew instead:

brew install --cask --adopt Jarvis322/tap/sysdata

Releases from 0.3.2 on are signed with a Developer ID and notarized by Apple, so the app opens without a Gatekeeper prompt. From 0.3.7 the binary is universal; 0.3.2 to 0.3.6 were Apple Silicon only and will not launch on an Intel Mac.

Build from source (Xcode 16 or later):

git clone https://github.com/Jarvis322/macos-sysdata.git
cd macos-sysdata
scripts/build-app.sh
open