Messed up trying to reformat now nothing works

Discussion in 'Mac Basics and Help' started by davidgolfer, Jan 4, 2016.

  1. davidgolfer macrumors regular

    Joined:
    Dec 1, 2015
    #1
    I'm new to mac and really know very little about what I'm doing. I was trying to clean install to erase everything, the MacBook was given to my son. tried to erase the partition from the boot option. Apparently this messed it up.

    I can boot into recovery mode but can't reinstall os x maverick or erase partition. When I try to delete or erase the partition it says can't unmount. This is a older MacBook with maverick not sure of the year.

    I tried making a bootable usb from my new imac w/yosemite. I can boot up and get the usb drive to boot. The problem when I try to install os x it doesn't see my hardrive. Why will Yosemite usb not see the drive?
     
  2. DeltaMac macrumors 604

    DeltaMac

    Joined:
    Jul 30, 2003
    Location:
    Delaware
    #2
    I think that you somehow had the hard drive partly erased, so you should try erase again...
    - that may get you going properly:

    Boot to your bootable USB installer.
    Run Disk Utility. That will be either on the main screen, or in the Utilities menu.
    If you see the hard drive listed in Disk Utility, choose that, then erase. Should only take a few seconds.
    Run Repair Disk on the newly erased hard drive.
    If that completes OK, you should be able to install OS X.
     
  3. davidgolfer thread starter macrumors regular

    Joined:
    Dec 1, 2015
    #3
    When I boot to the usb drive and go to disk utility the screen just says loading disks and spins for ever.
    --- Post Merged, Jan 4, 2016, Original Post Date: Jan 4, 2016 ---
    It's actually a MacBook Pro
    --- Post Merged, Jan 4, 2016 ---
    When I try to erase the disk from the hard drive recovery mode I get "disk erase failed, couldn't unmount disk"
     
  4. DeltaMac macrumors 604

    DeltaMac

    Joined:
    Jul 30, 2003
    Location:
    Delaware
    #4
    Leave your USB installer plugged in.
    Shut your MBPro off.
    Do a PRAM reset:
    Press and release the power button, then immediately press and hold Option-Command-P and R.
    You should hear the boot chime sound. Continue to hold those same 4 keys until you hear the boot chime 2 more times.
    Release the keys, except for the Option key. You should then see the boot picker screen. Click on your USB boot drive, then press enter. It should continue to boot to your installer. (the reset MAY get your hard drive to behave itself :D )
    Open Disk Utility, and try to get the hard drive to re-partition:
    Select the hard drive line, which will have the device model number. Then, click the Partition tab.
    Click the partition layout drop down, where you can select "1 Partition". Name the partition if you like, then press the Apply button. That process will reset the partition information on the hard drive, and erase the drive, making a single partition.
    That should take only a few seconds.
    Then, quit Disk Utility, return to the Installer, and that should let you go on with the OS X install.
     
  5. davidgolfer thread starter macrumors regular

    Joined:
    Dec 1, 2015
    #5
    Once I did this then booted into the usb drive, then go into disk utility it still just spins and says loading drives
     
  6. DeltaMac macrumors 604

    DeltaMac

    Joined:
    Jul 30, 2003
    Location:
    Delaware
    #6
    Nothing else attached, other than the power adapter, and the USB flash drive?
    How old is the MBPro? If you don't have any idea - the oldest models have aluminum colored keys, and the display bezel is also aluminum. All newer ones have black keycaps and black display bezel. That will at least get a range of age. 2008-2009 is when that trim changed over. If yours is older, then it's more likely the hard drive is just failing.

    In any event, you could pull the hard drive out, put it in an external case, and test it again. It's not uncommon for the internal SATA cable to fail.
     
  7. davidgolfer thread starter macrumors regular

    Joined:
    Dec 1, 2015
    #7
    it's around late 2010-early 2011 I looked up the model number
    Nothing else plugged in except power

    Weird thing is when I boot into hard drive recovery mode the drive shows up. It just doesn't when I boot from the usb. Can't figure out why.
     
  8. davidgolfer thread starter macrumors regular

    Joined:
    Dec 1, 2015
    #8
    Finally was able to get the drive erased and os loaded. Apparently when loading the disk utility under usb boot it was taking 30+ minutes. Left it when I went to work and it finally loaded. Thanks for the help.
     

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