So, my late 2012 Retina 13" running 10.8 has no CD/DVD drive. I've never repaired the disk or rebuilt the directory like I did regularly on previous Macs, using DiskWarrior. The machine has reached that age when it's developing a few quirks (slow loading of Google Search, forced restarts to escape freezes...) and my impulse is... repair! So how do I do that, with DiskWarrior no longer compliant and no way to boot from a CD? (I do have an external CD/DVD drive, if it's useful.) I verify with Disk Utility regularly, but learned decades ago to distrust it; Apple's bundled repair apps will say "All clear!" right up to moment the whole system melts. And, as above... I can't boot from optical anyway, so I couldn't click "Repair" if I wanted to. Sorry if this is much-asked question. I trawled around but didn't find a previous post on it.