OnyX
OnyX is a simple and powerful optimization tool for keeping you mac in top shape. This version requires Mac OS Mountain Lion, but other versions are available for Mac OS X 10.2 and higher. On running OnyX for the first time, it will run a S.M.A.R.T. verification check on the hard disk which helps in preventing any kind of system failures and will also makes sure that the volumes are clean so that you don’t experience an unusual volume structure. A good help guide aids application use with clear explanations and step by step guides.
With OnyX you can set the number of parameters to be checked by the application which can include Spotlight, iTunes, Expose and even Dock. The fonts, user and even system files are cleaned completely by this application. You will need to close applications to clean them properly though. This helps Onyx work faster and more efficiently. It also comes with an automation option which helps you in keeping your hard drive clean at all times and maintains any issues that occur in this part.
Those who have been facing system issues or start up issues with their Macs will find OnyX to be a useful utility. The application can also be used to delete logs from the computer or clear the system cache as well. It comes with a dialogue based interface as well and is a beginner friendly application. It is quite a flexible application too. It was launched only in 2003 and has a good development record. Overall, a good choice for all users.