Actually, you need Mac OS X no extra - Tools to clean up, optimize, etc ... But my Mac is currently 5 year old and started to spin. What I've done everything recommended, the error remained even after a complete new installation and the installation of a new hard disk (by authorized dealer). So I thought, as a last resort, I give 100 out and try it ... It worked, large amounts of defective files were found, with the possibility to analyze them before deleting. And my Mac is now running as the first day (Mountain Lion). From me - a clear recommendation for users who, like me, are not familiar with the depth of the system.