What OnyX is
OnyX is made by Titanium Software, a French developer that says it has been developing its apps since 2003. All of them are free and fully usable without registration, and donations are welcome. Titanium says it signs its apps and that Apple has notarized them (Titanium Software).
In Titanium's own description, OnyX lets you verify the structure of the system files, run cleaning and maintenance tasks, uninstall apps, configure settings in the Finder, Dock, Safari and some other Apple apps, delete caches, remove certain problematic folders and files, and rebuild various databases and indexes (Titanium Software, OnyX). Titanium also makes Maintenance, a smaller app with just the maintenance tasks, such as rebuilding databases and deleting caches.
Which version you need
There's a separate OnyX for each major version of macOS, and Titanium is direct about it: use the correct version, and don't try to use one made for an earlier system.
| Your macOS | OnyX version | Macs | Still updated? |
|---|---|---|---|
| macOS 27 | 5.1.1 (11 October 2026) | Apple silicon only | Yes; 5.1.2 is in progress |
| macOS 26 Tahoe | 5.0.6 | Apple silicon and Intel | No, still downloadable |
| macOS 15 Sequoia | 4.8.5 | Apple silicon and Intel | No, still downloadable |
To check your version, choose Apple menu › About This Mac. Download OnyX only from titanium-software.fr. It's also in Homebrew as brew install --cask onyx, which picks the build for your macOS, though when we checked, Homebrew still offered 5.0.5 on macOS 26 while Titanium's site had 5.0.6.
Is OnyX safe on Apple silicon?
The app itself, yes, as far as anything can be checked: it's from a long-running developer, it's notarized, and its current version is built for Apple silicon. What matters more is what its tasks do to your Mac, and that's mostly about cost rather than danger.
It can't touch macOS itself
Since macOS 11, macOS lives on a signed system volume: a read-only volume sealed with a cryptographic hash that the Mac checks while it runs, rejecting anything without Apple's signature (Apple Platform Security, Signed system volume). Without turning off Apple's protections, no utility, OnyX included, can change or "repair" those files. So "verify the structure of the system files" is a check, and the tasks that do change something work on caches, logs, databases, indexes and settings that macOS rebuilds or reads again.
What its tasks cost
- Deleting caches frees space for a while, then apps rebuild them, so the first launches afterwards are slower and use more energy. macOS already clears caches that are safe to delete when space runs low (Apple).
- Rebuilding the Spotlight index can mean hours of indexing, with mds_stores busy and searches incomplete until it's done. Worth it when search is broken, not as routine. What mds_stores is, and how long indexing takes.
- Clearing internet files, when that includes cookies and website data, can sign you out of websites, the same as removing website data in Safari does.
- Changing hidden settings for the Finder, Dock or Safari is reversible, but only if you remember what you changed. Note it down.
Some of its jobs no longer exist
The maintenance scripts that older Mac utilities ran daily, weekly and monthly were part of macOS's periodic system. On our Mac running macOS 27.0.1, neither the periodic command nor its /etc/periodic folder exists:
ls /etc/periodic
ls: /etc/periodic: No such file or directoryThat command only reads. MacPaw, for its part, now offers its own periodic-scripts task only on macOS 13 Ventura and earlier (MacPaw, Understand maintenance tasks). On current macOS, housekeeping runs on its own, which is why most traditional Mac maintenance is a leftover from older Macs.
What macOS already does for each job
| OnyX job | Built-in way | Worth doing by hand when… |
|---|---|---|
| Verify the disk | Disk Utility's First Aid, from macOS Recovery for the startup disk (Apple) | Apps or files behave strangely, or the Trash won't empty |
| Delete caches | Automatic when space is needed; safe mode clears font and kernel caches (Apple) | One app misbehaves and its developer suggests it. Clearing one app's cache |
| Rebuild the Spotlight index | Spotlight settings, or mdutil in Terminal | Search misses files you know are there |
| Flush the DNS cache | One Terminal command. How to flush DNS | A site moved and your Mac still goes to the old address |
| Uninstall apps | Drag to the Trash, then check your Library. Uninstalling completely | Every time you remove an app |
| Run maintenance scripts | Not part of current macOS | Nothing to run on current macOS |
If you use it
- Back up first. Let Time Machine finish a backup before running anything that deletes.
- Get the version for your macOS, from Titanium's site.
- Run one task for one problem. Pick the task that matches what's wrong, not every box in the list.
- Quit your other apps and keep a MacBook plugged in while tasks run.
- Give the Mac time afterwards. Expect caches and indexes to rebuild, and some extra fan or battery use for a while.
To remove OnyX, Titanium says to open the app and choose Help › Uninstall.
Where Tend fits
Tend's Maintenance page covers the handful of fixes that still help on Apple silicon, each with a note on when it's worth it. It lists your browser extensions and local Time Machine snapshots for free. With Tend Pro it can flush the DNS cache, rebuild the Spotlight index, tidy the Open With menu, remove local snapshots and remove extensions from Chrome and other Chromium browsers. It doesn't clean system caches or change hidden settings, and it has no maintenance-script or "free memory" button, because current macOS doesn't need one. For a broad toolbox, OnyX goes much further, for free.
Questions
Is OnyX safe for Mac?
Yes, as an app: it's free, from a developer that has made it since 2003, and signed and notarized. The risk is in running tasks you don't need. Deleting caches and rebuilding indexes cost time and battery afterwards, so back up and run only the task that matches your problem.
Does OnyX work on Apple silicon?
Yes. OnyX 5.1.1 for macOS 27 runs only on Apple silicon. The older versions for macOS 26 (5.0.6) and macOS 15 (4.8.5) run on both Apple silicon and Intel Macs, but Titanium no longer updates them.
Is OnyX free?
Yes. Titanium Software says all its apps are free and fully usable without registration, and it accepts donations. Download it only from titanium-software.fr or install it with Homebrew.
Which version of OnyX do I need?
The one for your macOS: 5.1.1 for macOS 27, 5.0.6 for macOS 26 and 4.8.5 for macOS 15. Titanium says not to use a version made for an earlier system. Check your macOS in Apple menu › About This Mac.
How do I uninstall OnyX?
Open OnyX and choose Help › Uninstall. That's the method Titanium Software gives on its site for removing its apps.
Related guides
Mac maintenance on Apple silicon
Which maintenance tasks still matter, and which are myths.
How to flush the DNS cache on a Mac
The one command, and when it helps.
What is mds_stores?
Spotlight indexing, and how to rebuild the index.
CleanMyMac alternatives
Free and paid options for each job a cleaner app does.
Sources
- Titanium Software, OnyX (versions, requirements, description), OnyX release notes, home page (signing and notarization, free apps) and Maintenance, checked 20 October 2026
- Homebrew, onyx cask, checked 20 October 2026
- Apple Platform Security, Signed system volume security
- Apple, Optimize storage space on your Mac
- Apple, How to repair a Mac storage device with Disk Utility
- Apple, Start up your Mac in safe mode
- MacPaw, Understand maintenance tasks (periodic scripts on macOS 13 and earlier)
Run the few fixes that matter, without the guesswork
Tend is free to download. Pro is $1.99 a month, $12.99 a year with a 7-day free trial, or $29.99 once.