Onyx: Simplifying Mac Maintenance

Gain access to hidden Mac features with OnyX

OnyX provides Mac users with a simple way to access hidden system functions, run maintenance scripts, automate repetitive system tasks, and access many of the parameters that enable or disable hidden features.

A free application, OnyX has been performing these services for Mac devices since the release of OS X Jaguar in 2002. The developer recently released new versions specifically for macOS Catalina.

Onyx is designed for specific versions of macOS. Make sure you download the correct one for the OS used on your Mac.

Onyx system utility for the Mac
Coyote Moon, Inc.
What We Like
  • Easy access to many hidden Mac features.

  • User interface is easy to use.

  • Convenient help files tied to each page of Onyx.

What We Don't Like
  • Only a single automation process supported.

  • Always asks to verify startup drive.

Using Onyx

The functions available in Onyx utility are mostly present in other apps or system services. Onyx's real service is in bringing them all together into one app.

When you first run Onyx, it will ask to verify the structure of your Mac's startup disk. While a good idea, this will force you to wait some time before using Onyx. You will not need to perform this task every time you run Onyx; you can simply cancel the verify option. If you find a need to verify your startup drive at a later date, you can do so from within Onyx, or use Disk Utility to perform the verification.

After you move past the startup drive verification, you will find that Onyx is a single-window app with a menu bar for selecting various Onyx functions. The toolbar contains buttons for Maintenance, Cleaning, Automation, Utilities, Parameters, Info, and Logs.

Info and Logs

Info and Logs are basic functions. Most people will not use them more than a few times.

Info provides a list of malware identified by your Mac's built-in malware detection system. It does not provide information detailing whether the system ever caught any malware being downloaded or installed — only the list of malware types your Mac is protected from. This is helpful if you'd like to know when the last update to the protection system was performed.

The Log button brings up a time-based log detailing every action performed by Onyx.


The Maintenance button provides access to common system maintenance tasks, such as verifying Mac's startup drive, running maintenance scripts, rebuilding services and cache files, and repairing file permissions.

Permissions repair used to be a standard troubleshooting tool with macOS X, but with macOS El Capitan, Apple removed the permissions repair service from Disk Utility as something that was no longer needed. The file permissions repair feature in Onyx works just like the old Disk Utility permissions repair system. It may not be needed because Apple started protecting system file permissions in El Capitan and later, but it doesn't seem to have any detrimental effect.


The Cleaning button allows you to delete system cache files, which can sometimes become corrupt or unusually large. Either issue can cause problems with your Mac's performance. Removing cache files can sometimes correct problems, such as a spinning pinwheel of death and other minor annoyances.

Cleaning also provides a way to remove large log files and erase files securely.


Automation is a handy feature that lets you automate routine tasks you may use Onyx for. For example, if you often verify the startup drive, repair permissions, and rebuild the LaunchServices database, you can use Automation to perform those tasks for you instead of manually performing them one at a time.

You cannot create multiple automation tasks — just a single one containing all the tasks you want to have executed together.


Onyx provides access to many of the hidden apps that are already present on your Mac but stashed away within the recesses of the system folder.

You can access the Terminal's manual pages without having to open the Terminal app, change file and disk visibility, and generate checksums for a file, which is helpful when sending files to others. You can access hidden Mac apps, such as Screen Sharing, Wireless Diagnostics, Color Picker, and more.


The Parameters button gives you access to many of the hidden features of the system as well as individual apps. Some of the features are already present in System Preferences, such as showing graphics effects when opening a window. Others usually require Terminal to set up, such as the graphics format used to capture screenshots. There are some interesting options for hacking the Dock, including the option to only reveal active apps in the Dock.

The Parameters button gives you control over many of the GUI elements of your Mac, letting you personalize the interface and alter its look.

Final Thoughts

Onyx sometimes gets a bad rap from advanced Mac users who complain that it can cause problems by deleting files or turning off features that are needed. The other frequent complaint is that Onyx does not do anything you cannot already do with Terminal or other apps present on a Mac.

There's nothing wrong with using a utility such as Onyx to perform a task usually performed in Terminal. Terminal requires you to remember complex command lines that, if entered incorrectly, can either fail to work or perform some task you didn't mean to run. Onyx removes both the barrier of remembering commands and the unfortunate side-effects of executing a command incorrectly.

Onyx provides easy access to many key system features and services. It also provides some basic troubleshooting services that can help you get your Mac working again or deliver increased performance. All in all, it is a useful tool.

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