- Entirely free
- Great maintenance functionality
- Stellar cleaning functionality
- Automated cleaning and maintenance
- Utilities enabling access to macOS' hidden features
- Detailed list of identified malware
- No detailed data of reclaimed disk space
- Lacks option to review files before deleting
- Specific version of OnyX for each major OS version
When it comes to maintenance, one of the most frequently mentioned applications among Redditors and longtime Mac users is OnyX. Created by French developer Joël Barrière as a multifunctional tool for Mac optimization, OnyX lets you control many basic Unix programs already built into macOS. Such controls include verifying the startup disk, running a range of miscellaneous and cleaning tasks, configuring various parameters, deleting caches, and listing all installed items included in the package files of applications that users have installed on their computer.
OnyX is freeware and the main application Joël Barrière has developed after the launch of OS X Jaguar, in 2003. Titanium Software, his company’s website registered as a French domain, lists another two applications also developed by Barrière, Maintenance and Deeper. The former is a system maintenance and cleaning utility for macOS that takes OnyX's maintenance functionalities and puts it into a separate app, while Deeper focuses on offering personalization options for macOS users, such as enabling or disabling the hidden functions of various apps and more.
OnyX features a nice, clean, easy-to-understand user interface that makes all features easily accessible. When you first open the app, it will display a prompt explaining that OnyX will verify the structure of your startup disk. If you click “OK” you'll notice your computer slow down a bit (which is common when this task is performed with Mac optimization tools) though apps such as MacBooster or CleanMyMac only perform this when you command them to do so. You can disable this functionality in preferences, otherwise it will display this prompt each time you launch the application.
If this task results in a startup disk in good working order then OnyX will display its available functions: maintenance, cleaning, automation, utilities, parameters, info and log. The main features of the app, which are recommended for regular use, are the maintenance and cleaning functions, while the automation functionality is the combination of these two.
Choosing between either the ‘automation pane’ or the maintenance and cleaning panes will depend on how much time you are willing to spend on Mac optimization. You can remove cache files from System folders using either the System pane of the cleaning toolbar or the automation pane. Still, there is a slight difference between the two cleaning options: while the automation tool will perform all the cleaning and maintenance tasks in a single workflow and therefore only require a single Mac restart once the tasks are finished, choosing maintenance and cleaning actions separately will need multiple restarts throughout the process.
When you hit the “Execute” button, OnyX scans your computer and performs the tasks you have commanded. Don't expect too many visuals, however: unlike its paid competitors such as MacBooster or CleanMyMac, OnyX won't display findings such as the number of cookies or browsing history items it has identified while scanning your Mac. Neither will you know how much space the app will reclaim by deleting the system, user, font and application caches. That's information the developer didn't consider important with any of the app releases. Paid Mac optimization apps, on the other hand, focus heavily on visuals and such data.
During our testing a completely automated maintenance and cleaning task took a little more than seven minutes to finish on a MacBook Pro (late 2016) with 250GB of flash storage. Of course this will differ by computer since it depends on a number of factors, including system configuration, disk storage, stored data and more.
If you decide to spend more time on maintenance and cleaning, choosing tasks individually will require more of your time. Also, some of the tasks – such as cleaning the system, user and font caches and log files – will require a restart each time. That's something you should keep in mind.
Along with cleaning and maintenance tasks, OnyX includes several other powerful features, such as utilities, parameters, and info. Under the utilities toolbar users will find various useful functions, ranging from gaining access to all of the Unix manual pages to changing the visibility status of a disk, folder or file. The ‘packages' task in Utilities will also look for a receipt file (.BOM) of an installed package (.PKG), and contains a list of all installed items stored in a system folder.
The parameters toolbar will enable you to personalize your working environment and toggle on or off certain hidden system functions and Apple applications. For example, with the Parameters toolbar it is possible to change the screenshot file type from its default of PNG to JPEG or change the save path for screenshots from the default location – your desktop – by clicking on the “Select” button, picking a desired folder and confirming it with the “Choose” button.
A very powerful feature of the software is the info toolbar, which includes tools such as ‘protection’. In this pane you'll see a list of malware recognized by XProtect, the macOS protection system. You’ll also be able to show and delete the list of all downloaded items tested by XProtect. In our testing, XProtect recognized 77 malware items, according to the malware definitions.
OnyX is freeware, meaning that you can download the application and use it for as long as you wish without paying a cent. If you like the application, you’re also allowed to distribute it, providing the software is not modified. Although the app is free, the developer accepts donations where you decide the amount. That compares to the $40 that OnyX's competitors MacPaw and IObit charge for a single Mac license. The developer pushes out updates regularly on its dedicated website Titanium-Software.fr.
Since OnyX is a free app and is mainly developed by a single person with the help of others from around the world, it doesn't have a dedicated customer service. Still, if you encounter a problem or anomaly, a misspelling or bad translation, or you have any suggestions for OnyX enhancements then you are free to contact the developer via email.
It is recommended that you back up your Mac when using OnyX for the first time, just in case anything goes wrong. However, we should note that we have been using OnyX for many years now and have had no issues with the software.
OnyX also includes a help file that offers a detailed description of every action and task the application performs, unlike some of its competitors like MacBooster. So, if you don't understand a command you are about to execute, just click on the question mark in the bottom-right of the app window and a help page will open to answer your question regarding OnyX's command.
Although macOS has built-in maintenance and cleaning scripts, a third-party application can be helpful in an effort to reclaim disk space occupied by cache files. What highly advanced macOS users familiar with Terminal can achieve by typing in complex command lines, OnyX – a reliable and free third-party Mac optimization application – does with a clean and easy-to-understand user interface.
OnyX doesn't deliver much detailed and visually organized information about the free space you are going to regain, but it still does a good job of reclaiming ‘lost space’. Functionalities offered by paid third-party competitors, such as freeing up memory, are also included in the app, although they are a bit hidden.
If you are looking for a reliable Mac optimization app to try risk free, OnyX is the one to start with. OnyX has been available for free since it was first released in 2003.