Onyx is one of the best free maintenance tools for Macs. However, I’ve noticed a bug with it recently that could cause some users to panic. On starting the application and allowing the start-up disk test to run, Onyx displays a “The volume needs to be repaired” warning, referring to the start-up disk.
I did what Onyx asked for. I inserted the Snow Leopard installation disk, held down the “C” key to force the Mac to boot from the disk and then ran Disk Utility to repair the startup disk. After Disk Utility reported everything was fixed correctly, I restarted my Mac, ran Onyx’s startup disk test again and got exactly the same error message!
I’ve tried with both the stable and latest beta release of Onyx and the problem persists. It seems that this is an issue affecting many users, even including people who have just bought new Macs, so it’s probably safe to say that it’s a bug in the program, and not a sign that your start-up disk is about to fail!
However, it is still highly advisable to back up everything before using Onyx, just in case.