OnyX is a Mac cleaner which enables you to verify the startup disk and the structure of the system files. Here are a few ideas of what OnyX has to offer to mac users. Having OnyX for regular mac maintenance procedures is for most people he most reliable way t have your mac cleaned and properly maintained. What is worse is that they might even end up malfunctioning or even cause other applications t malfunction. It is free to use, highly reliable and easy to navigate.