OnyX is an all-in-one system maintenance tool and optimizer. It is a very simple and light application that comes with a variety of maintenance tools that can be run to make sure that you are enjoying your system at its fullest.
Not everything that OnyX can do deals with hard drives, though. In the main window, there are five categories. The first one is hard drive analysis and restoration, but the following ones allow you to repair the permissions of your system (a common problem with Macs), clear your browser settings, cache, passwords, etc., delete application, user and system caches, and more.
An array of more advanced features is also available. Those allow you to hide or show volumes, repair discs, run custom scripts, among others.
OnyX comes with extensive help and it even includes a glossary with the information about many tasks. Although Macs are known for their stability and lack of errors, it can never hurt to have an application like this.
Pros
- Quick analysis
- Multiple repair options
- Built-in glossary
- Several different types of checks
Cons
- Slow when working with certain drives
It would be fine, if the updater (mac.informer) verifies the current OS-version before propose the update. Otherwise you have to expect many problems to remove the unmatched version and reinstall the old but working one.
Don't simply rely on download sites (MacUpdate, etc.). If you go to the developers site, they have versions of Onyx available for old versions of OS X as well as M/L. They say they're soon to release the Mavericks version as well.
For Mountain Lion only! Does not work with Lion.