This disk cannot be used to startup your computer?!?

Discussion in 'OS X Mountain Lion (10.8)' started by Blakeasd, Jul 25, 2012.

  1. Blakeasd macrumors 6502a

    Dec 29, 2009

    I just purchaed Mountaion Lion, but I can't install it. The installer keeps saying "This disk cannot be used to startup your computer" even though I am using that disk right now. I tried making the partition smaller, like the support document said when updating from SL to Lion -- I am going from Lion to ML. I checked to see if my MacBook is supported and it is. Maybe it has something to do with my computer not having a Recovery partition (I was trying to dual boot Ubuntu [unsuccessfully] and ended up messing with a bunch of drive stuff) Can somone please help me, I'm stuck!

    I am running OS X Lion on a Late 2009 White Macbook

  2. rawdata, Jul 25, 2012
    Last edited: Jul 25, 2012

    rawdata macrumors newbie

    Jul 25, 2011
    Same here. MBP mid-2010. I had reEfit installed but removed before installation.
  3. souloxide macrumors newbie

    Dec 8, 2011
    Try this...

    I had the same problem earlier.. Finally, after several attempts...

    1. Create a new partition (dont make it too big - i used 128gb)
    2. Erase free space of that new partition (fastest is fine)
    3. Reduce partition size of the original mac hd (approx 128mb.. Could be more)
    4. Re-install mountain lion and it should work (hopefully)

    I think you can interchange step 2 and 3.. Probably doesnt matter

    Good luck!
  4. rawdata macrumors newbie

    Jul 25, 2011
    Just a quick update on this, I've used this solution and it worked for the install.

    Now can't get my partition back to normal size and the volume keys stopped working....
  5. MobiusStrip macrumors regular

    Dec 11, 2009
    Which part of that “solution” did you use? The document presents several options, and doesn’t appear to address this issue.

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