OnyX is a free maintenance and configuration utility for macOS, made by Titanium Software. It verifies the startup disk and the structure of system files and cleans out caches and other accumulated data. It also removes applications along with their leftovers and switches on hidden settings in Apple’s own apps. Many of these tasks would otherwise require Terminal commands. OnyX turns them into options you select in a window. It needs no registration and has no paid tier.
Disk and system file checks
The verification side of OnyX looks at the startup disk and at the structure of the system’s own files. Because it works on the core of the operating system, Titanium Software builds a separate edition of OnyX for each major macOS release. You should not run an edition meant for an older system on a newer one.
Caches, logs and leftover files
Cleaning is the part of OnyX most people open it for. It deletes application caches, font caches and system caches, along with files and folders that are known to cause problems.
Beyond caches, OnyX can clear several kinds of accumulated data:
- application logs
- internet files and browser history
- the Recent Items lists
- downloaded screen savers, and downloaded wallpapers for all user accounts
Rebuilding databases and indexes
macOS keeps a number of databases and indexes that apps and the system rely on. When one of them is out of date or damaged, OnyX can rebuild it. This saves typing the equivalent command-line instructions.
Removing applications
Dragging an app to the Trash leaves its support files, preferences and caches behind. The uninstaller in OnyX removes an application together with its related files and folders. An option lets you delete or keep the main application itself. This lets you strip out an app’s accumulated data while leaving the app installed. Another option limits the list to applications that are currently open.
Hidden settings for Apple apps
OnyX gives you switches for settings that Apple does not show in its own preferences. These cover the Finder, the Dock, Safari, Music, the login window and several other Apple applications. Each one would normally require a command typed into Terminal. In OnyX, you can switch it on or off again from the same window.
Hardware and system information
An Info section reports details about the Mac. Its Hardware pane lists details about the machine, including its current thermal state.
Tools folded into OnyX
Titanium Software also offers several single-purpose apps whose functions are already part of OnyX. Maintenance handles cache cleaning and database rebuilds, while Deeper handles hidden settings. Uninstaller handles app removal, and CalHash calculates and compares a file’s checksum. Schedulizer sets times when the Mac starts up, shuts down or goes to sleep. Anyone running OnyX does not need these separately.
OnyX supports light and dark appearance and is available in many languages. It installs no background processes, and it can remove itself through its Help menu.
