Diskzy vs OnyX: an honest comparison
OnyX from Titanium Software is a multifunction maintenance utility. Its site describes verifying the structure of system files, running maintenance and cleaning tasks, deleting caches, rebuilding databases and indexes, and changing hidden settings in Finder, the Dock, Safari and other Apple apps. It is free to use, with donations invited, and there is a separate version for each major macOS release. Its site tells you to use the version made for your system.
Diskzy has a narrower job. It does not run maintenance scripts, rebuild databases or change hidden settings. It shows where disk space has gone, explains System Data part by part, suggests what to clean with a reason for each item, and uninstalls apps with their leftovers. What it removes goes to the Trash, so a cleanup can be undone until the Trash is emptied.
| Diskzy | OnyX | |
|---|---|---|
| Price | Free for 72 hours with everything unlocked, then $9 once for 2 Macs. No subscription. | Free to use. Donations invited. |
| Focus | Disk space: what is using it and what can safely go. | System maintenance: verification, maintenance tasks, cache deletion, rebuilding databases and indexes, hidden settings. |
| Disk map | Maps the whole disk, with search by name, kind, size or age. | Not stated |
| System Data | Breaks System Data into named parts, each sized and marked Safe to clear, Look first or Managed by macOS. | Not stated |
| Cleanup | Clean up tab lists caches, logs, Xcode leftovers, project build folders, package-manager caches and old installers, each ticked or unticked with a reason. Open apps are left alone. | Yes. Deletes caches and removes certain problematic files and folders as part of its cleaning tasks. |
| Maintenance tasks and hidden settings | No. | Yes. Maintenance tasks, rebuilding of databases and indexes, and settings for Finder, the Dock and Safari. |
| App uninstaller | Yes, with leftovers. | Not stated |
| Where deleted files go | The Trash. Nothing is gone until you empty it. | Not stated |
| Requirements | macOS 15 Sequoia or later, Apple silicon and Intel. | A specific version for each major macOS release, going back many years. You must use the one that matches your system. |
When OnyX is the better choice
Choose OnyX if you want a free maintenance utility, need to rebuild a system database or index, want access to hidden macOS settings, or run an older macOS version that has its own OnyX release.
When Diskzy is the better choice
Choose Diskzy if your question is where the disk space went. It shows the whole disk, explains System Data, gives a reason for each cleanup item, and sends removals to the Trash.
Details about OnyX were checked on October 10, 2026 against titanium-software.fr. Prices and features change; check their site for the latest.
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See where your Mac's space went
Diskzy maps your disk, explains System Data and clears what's safe. Free for 72 hours, then $9 once for 2 Macs.
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