Hello all I have a Mac that has this weird problem. It's a used Mac and I've no idea what the previous owner did. This Mac has a 750GB drive but the OSX partition only has 100GB. Disk utility doesn't recognize the entire disk so there's no way for me to resize the OSX parition. All I want is to perform a clean re-installation of OSX onto the entire 750GB drive and but since disk utility only recognizes the 100GB I'm unable to do so.

Can someone help me? I can work with Terminal commands if that will fix the problem.

(Click image to enlarge)


I'd go for the full Cmd ⌘ Opt ⌥ R at boot & work from Internet Recovery.

Nuke & pave.

Disk utility won't let you do much at all with the boot drive if you're booted from it.
You also don't want to inherit any legacy from the previous owner. At the moment you don't even own the OS that's on it.

  • Thanks! Any suggestion/tutorials on Internet recovery? – Alex Su Nov 24 '15 at 10:43
  • support.apple.com/en-gb/HT201314 Also includes what to do if it doesn't go smoothly, so you don't get stuck :) ..though the 'if all else fails' solution is go to an Apple Store, they'll do it for free. – Tetsujin Nov 24 '15 at 10:45
  • That's one of the options I was thinking of(we were discussing this on chat) , but I don't know all that much about macs. From which version does internet recovery work? – Journeyman Geek Nov 24 '15 at 11:21
  • Anything that initially shipped with Lion 10.7 or later & some slightly earlier models, if they had a firmware update So most machines later than 2010 – Tetsujin Nov 24 '15 at 11:35
  • 1
    Tried the Internet Recovery option, disk utility from it recognized the 750GB drive. Thanks guys! – Alex Su Nov 24 '15 at 12:02

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