Disk won't unmount

Discussion in 'macOS' started by MagicHAM, Dec 12, 2015.

  1. MagicHAM macrumors regular

    MagicHAM

    Joined:
    Sep 2, 2013
    Location:
    Australia
    #1
    Hey guys,

    I am trying to reformat my Macbook's hard drive as i am giving it to my mum as i have a new macbook and im trying to reinstall Mac OS X Lion on it. (The original firmware that came with it), hiowever there seems to be problem when i tried to unmount it through disk utility - it says it cant be unmounted.

    Currently I am running Mac OS X El Capitan on it, but no matter what i do in Disk Utility in the boot up USB for Lion it just wont unmount it, I tried to repair and verify the disk repairs in Mac OS X El Capitan but says it needs to be repaired and reformatted, but clearly I can't do it.

    I am thinking a dead hard drive? At this point.... Any suggestions?
    I backed up all my info from the drive anyway.

    But what am i doing wrong here?
     
  2. MagicHAM thread starter macrumors regular

    MagicHAM

    Joined:
    Sep 2, 2013
    Location:
    Australia
    #2
    I cant seem to get the disk to unmount on the disk utility in my setup disc that i got with the mac either. I don't know why this isnt working. I am not exactly a pro at this, but im guessing a hard disk failure at this point, but i don't know what else to try, can anybody suggest?

    I will be posting any error messages i recieve, and googling them myself, but will also post them here just in caes if anyone knows anything.
     
  3. MagicHAM thread starter macrumors regular

    MagicHAM

    Joined:
    Sep 2, 2013
    Location:
    Australia
    #3
    These are the errors i found and i am going to try and click repair.

    "Volume bitmap is corrupt"
    "The volume (insername) was found corrupt and needs to be repaired."
    "This disk needs to be repaired. Click repair Disk.

    I got this about an hour ago when i tried to do this with the Recovery Console of El Capitan but it wouldn't repair the desk.

    Going to try it again. (What can i say i am persistant)

    It did it again - all the installers i tried to repair the disk - it won't umount the hard disk. Just says Could Not unmount hard disk.

    The partition is set to Mac Jouranlized so it's in a mac OS file system that can be read.

    I'm at a loss can anyone give me some ideas on what to do now?
     
  4. MagicHAM thread starter macrumors regular

    MagicHAM

    Joined:
    Sep 2, 2013
    Location:
    Australia
    #4
    Smart Status says its Verified and the partition Map Scheme says GUID partition Table. If that helps.
     
  5. DeltaMac macrumors 604

    DeltaMac

    Joined:
    Jul 30, 2003
    Location:
    Delaware
    #5
    Boot to Internet Recovery.
    Restart, while holding Option-Command-R
    You will see a rotating globe, not the normal grey Apple icon. That tells you your MacBook is booting to Apple's remote servers. It can take longer to finish booting, maybe 3 to 5 minutes. You should see a button to Reinstall OS X. Don't do that yet. Open Disk Utility, and erase the hard drive. If that erases without showing an error, quit Disk Utility, and continue with the OS X reinstall. It should offer you Lion.

    If there is a problem with the hard drive, the erase may fail. Best next step then will be to replace the hard drive. (It is 5 years old or more) Not too difficult to do replacement. And, consider using an SSD instead of a hard drive. You will see a considerable increase in performance, better than when it was brand new.
     
  6. MagicHAM thread starter macrumors regular

    MagicHAM

    Joined:
    Sep 2, 2013
    Location:
    Australia
    #6
    Firstly - I don't need internet recovery, because firstly i want to erase the hard drive, and SMART status says its verified and the hard drive is working. And I have a USB installer, and a Mac OS 10.6 disk that i can install (or have been)

    I cant even unmount the hard drive from disk utility. It says "Cant Unmount" . I have given a lot of information and i have included that.

    Thanks
     
  7. DeltaMac macrumors 604

    DeltaMac

    Joined:
    Jul 30, 2003
    Location:
    Delaware
    #7
    Thanks for your gracious response, but I seldom, if ever "cut and paste" here - I was only suggesting an alternate plan that SHOULD work, despite your annoyance with that suggestion. You can choose to ignore that suggestion, fine with me...
    The reason I suggested Internet Restore is that generally takes local effects out of the way.

    In your prior posts, you did not mention if you have tried both PRAM and SMC resets.

    Here's how I would proceed - Do you have a USB installer for either Yosemite or Mavericks? Boot to the USB installer. Run Disk Utility from that. Yosemite, or Mavericks Disk Utility will have an easy method to reset the partitions, compared to the (castrated) El Cap Disk Utility.
    Select your hard drive (not the named partition), then the Partition tab, Click on the Partition Layout dropdown list. Choose 1 Partition from the drop down, then click Apply. That MIGHT clear your drive then.
     
  8. BLUEDOG314 macrumors member

    BLUEDOG314

    Joined:
    Dec 12, 2015
    #8
    Your drive is more than likely fine if SMART is verified, no need to replace. Go to recovery or the install image and jump into terminal.

    Type: diskutil cs list

    If it displays a bunch of stuff and doesn't say something along the lines of 'no core storage volumes found,' then you have to break up the Core Storage logical volume group first. You should see something like 'Logical Volume Group: 123ADGF-3953-DSCB43G-0682BIAG.' Copy that string of random numbers and letters to the clipboard, then...

    Type: diskutil cs delete 123ADGF-3953-DSCB43G-0682BIAG

    execute this, then quit terminal and try to use disk utility again to erase and format like you were trying before.

    If there were no core storage volumes found in the first place...

    Type: diskutil list

    From here identify your internal disk identifier. It should and usually always is disk0.

    Type: diskutil erasedisk jhfs+ "Macintosh HD" disk0

    If that executes and does not give a cannot unmount error quit terminal and try the install again.

    If this does not work...

    Type: diskutil unmountdisk force disk0

    Again using disk0 or whatever you found above. If this works, again,

    Type: diskutil erasedisk jhfs+ "Macintosh HD" disk0

    Now try the install again. If none of this works, post back and I'll give you something more advanced to try.
     
  9. MagicHAM thread starter macrumors regular

    MagicHAM

    Joined:
    Sep 2, 2013
    Location:
    Australia
    #9

    That was one of the things I tried.... Didn't work. But thanks for suggesting that though.

    Hi will give that a shot. Will post back how I go.
     
  10. MagicHAM, Dec 12, 2015
    Last edited: Dec 12, 2015

    MagicHAM thread starter macrumors regular

    MagicHAM

    Joined:
    Sep 2, 2013
    Location:
    Australia
    #10

    Tried all those just now it says the same thing when I tried to unmount even with the force option. It fails and could not be us mounted.

    Okay I decided to do something I decided to erase the volume instead and that indeed did the trick.

    Looked at the specific volume I needed disk0s2 and so i typed that In and that did the trick. Just installing Mac OS lion now. Let's hope it works.
     
  11. MagicHAM thread starter macrumors regular

    MagicHAM

    Joined:
    Sep 2, 2013
    Location:
    Australia
    #11
    Sorry I snapped at you. Was just frustrated Coz I'm not farmilar with the Mac OS terminal or how things operate.. Guess it's time to learn huh. Lol
     
  12. DeltaMac macrumors 604

    DeltaMac

    Joined:
    Jul 30, 2003
    Location:
    Delaware
    #12
    There's almost always multiple choices for repairs. Some end up actually helping. Glad you got it working again!
     

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