Yes, Onyx is a reliable, useful utility that has been around for quite some time. And yes, you must get the appropriate version for the OS you are running. I don't think Titanium Software is upgrading any versions of Onyx prior to the one for El Capitan. But, as long as you have the last version for the OS you are using, you will be fine.
I count on Onyx as part of my disk maintenance/repair arsenal (the other one is TechTool Pro (I also have Disk Warrior)). And, I will not upgrade to a new Mac OS until Onyx (and at least 4 other critical products) are either OK, "as is", or until an update comes out.
Last edited by honestone; 12/17/15 04:59 AM.
