When you open OnyX a few things will happen. First it will ask to verify the S.M.A.R.T. status of your disk. This is something important because it will look for errors on your hard drive. If it finds something it will alert you. This is a good way to know if your drive is failing. If your drive fails a S.M.A.R.T. test it is a good idea to look into getting a new hard drive. After that you will be prompted to test your startup volume. This is another good test to run but please be aware that it will cause all of your programs to quite when it runs. Be sure to save all of your work before you run the test to prevent loss of work.
Once these tests are done you will need to enter your password. Before it lets you get in and clean, and maybe change settings on your computer, it wants to verify that you are the person responsible for the changes. This prevents someone from messing up your computer without your knowledge. Along with the interface is a guide to help you use OnyX. It tells you to be sure to backup all of your work incase you make a mistake using OnyX you can go back and get any lost work. Be sure to review the guides provided by them and follow the suggestions they give before trying anything on your system.
The first part of OnyX is the "Verify" section. Clicking on it will show you a pane where you can go back and run the S.M.A.R.T. Status check and the Startup Volume check again as well as checking the .plist status. These test will show you how your system is running and help you know what else you need to do based on the results of the test.
The Next section is Maintenance. Through this tab you can view and repair permissions, check the scripts or logs of your computer and rebuild any indexes or databases you need to. Most of this can be done through DiskUtility which comes built into every Mac but OnyX seems to be a much easier way to get things done. The maintenance section will make sure all of the files line up where they need to be so that they are easily discovered on your hard drive and they allows you to make sure your scripts are being cleared as needed. Sometimes people don't use their computers that often and because of the computer being off or asleep the cleaning out of the scripts doesn't happen during its programmed time. This will allow you to clear those out so that they don't become overloaded.
The next section is "Cleaning" it is important to remember to keep the internal workings of your computer just as clean as you would keep your screen or keyboard. Each of the different sections within the cleaning field searches the files it describes looking for partial files, corrupt files or anything else that may be causing you problems. If you are using an Application or anything on your computer and keep having issues it is a good idea to come here execute a clean on your system and see if that helps to fix the problem.
The next two sections are the ones you want to be careful with. The "Utilities" and the "Automation" sections can cause some issues if you do the wrong thing. If you are not familiar with what you see in those sections I suggest not going into them too much. I will go into detail about those sections in a later post because i feel they need more attention so if you want to skip over them it might be a good idea for now and we will come back to them soon.
The "Parameters section is where you can have some fun and make some useful changes to your computer. Through here you can go in and make little changes to the Finder, Dock, QuickTime, Safari, iTunes, the Login, and Spotlight. The general tab lets you make some changes to backgrounds. If you use this be sure that you have a powerful computer. Running an animated background is very taxing on the computer so you need to be sure that you have the power need to keep it going and still use all of your other applications up to standard. One of the features I really like in the general setting is the ability to change the Arrows in the scroll bar. I like the double arrows at both ends. It makes for easy clicking no matter where your mouse is. You can change your dock from the 3D dock to a 2D dock in the dock section and also change how your items move in and out of the dock. Most of these changes are to make your Mac into something you like better. Feel free to play with them and see what it does.
The "Info" section is a lot like the about this Mac section. It gives you general information about your computer like the serial number and what version of the OS you are running. It tells you how big your hard drive is and how much of it is being used. It will tell you how long your computer has been on since the last boot and provides other useful information about your computer.
All in all OnyX is a very clean and nice application that you can use to help you keep track of things and make sure your Mac is running the way it should. I find it easy to use and I like the added features it gives me to customization of the user interface of my computer.