Adjust Hidden Mac Preferences with Onyx

There are plenty of options that you can configure in the System Preferences of macOS, but if you find that insufficient to fulfill your needs to customize the system to the fullest, you can check out Onyx, a free maintenance and customization program that uncovers hidden preferences for macOS.

Downloading and Installing Onyx

1. Download Onyx from the developer’s website. There’s a specific version of Onyx for each version of macOS, so make sure you download the right one.


2. Install Onyx from the downloaded disk image.

Starting Onyx

1. Open Onyx from the Applications folder.


2. Enter your administrator username and password because in order for Onyx to fiddle with deep system functions, it needs admin access to run. It won’t make any changes until you actually do something, so you can click “OK” without fear.


3. You’ll also need to agree to Onyx’s terms of use. After you read them, untick “Display at launch” to avoid seeing the agreement at each launch. Click “Agree” when you’re done.


4. Here’s our final preparatory step: Onyx likes to verify the structure of your system disk up front. You don’t have to do this if you’re only planning on using the customization features of Onyx, but it should only take a moment and will reveal any potential problems with your startup disk. Click “Continue.”


5. Once the disk verification has been completed successfully, click “OK.”


Revealing the Customization Menu

1. Click on the “Parameters” menu item in the Onyx menu bar.


2. Wait for the macOS parameters to be read from the file.


3. This will reveal the master parameters menu which is where we’ll do our customization.


“General” Customization

The “General” menu contains many of the most useful system tweaks in Onyx.

1. Under the “Misc. options” menu, you’ll find a few settings you can tweak.


  • Show graphic effects when opening a window: toggle visual effects for opening and closing windows.
  • Show the rubber-band scrolling: toggle iOS-style “bounce” behavior that occurs when you try to scroll past the end of a window.
  • Show the location path of the current desktop picture on the desktop: Show the file path of the desktop image in the middle of the desktop.
  • Turn on the accent menu from the keyboard: toggle the ability to access the accent menu from the system’s keyboard.

2. Speed of display sheets: adjust how quickly “sheets,” or temporary program dialogs, are hidden and revealed.


3. Speed of display of help tags: adjusts how quickly tooltips will appear when you hover your cursor over an interface item, like a button.


4. Animated desktop background: allows you to choose from a list of preset animated backgrounds for your desktop.


Customizing your screenshot settings


1. Screen capture format: sets the file type for future screen captures.


2. Display shadow in window captures: Toggle the “drop shadow” effect applied to full window screen captures.


3. Include the date and the time in the name of captures: Toggle the appearance of date and time in your screen capture’s filenames. If you turn this off, your screen captures will be numbered sequentially to avoid overwriting.


4. Path: change the location where new screen captures are saved. Click the “Select …” button to open a Finder window and choose a new location.


5. Name: change the string that starts the name of a screen capture. If you leave “by default,” files will be named with “Screen Shot.” You can replace that text with anything you want, provided it’s allowed by the file system.


Making Changes

When you make changes, Onyx will typically ask to restart a service to apply that change. For example, if you change the path of your screenshots, you’ll need to restart the SystemUIServer process.


Click “Continue” in the dialog box, but first confirm that the restarting process isn’t in the middle of an operation. That’s not important for something like SystemUIServer, but be careful with apps like Finder.

Other Customizations

There are many more customizations available in Onyx than can be covered in one post, but here are a few favorites.

Set a custom login background picture

1. Click the “Login” tab.


2. In the “Background” section, click the  “Select…” button to open a Finder dialog and pick a new image. Only PNG files are compatible.


Show a message at login

1. Click the “Login” tab.


2. Check “Show message in the login window.”


3. Type a message that will be permanently visible to all users at login, then click “Apply.”


Turn off disk image verification

1. Click on the “Applications” tab.


2. Uncheck “Verify disk images (.dmg).”


Turn off Time Machine Local Backups

1. Click on the “Misc.” tab.


2. Click the “Turn Off” button next to “Time Machine local backups.”


Turn off the Notification Center

1. Click on the “Misc.” tab.


2. Click the “Turn Off” button next to “Notification Center.”



There is a lot more that Onyx is capable of, so explore the “Parameters” menu to find more options.

Alexander Fox
Alexander Fox

Alexander Fox is a tech and science writer based in Philadelphia, PA with one cat, three Macs and more USB cables than he could ever use.

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