gabrielknight1
Level 1 (8 points)
Mac OS X

Q: diskutil cant erase disk in terminal Mavericks Install

Im trying to start a complete new install of Mavericks from a USB file but im having trouble getting diskutil to erase all the partitions on my HDD, it has 2 partitions "Macintosh HD" and "Recovery HD" but when im in the terminal and use:

 

diskutil eraseDisk JHFS+ Test /dev/disk0 , it says it could not unmount the disk. I tried to install Mavericks from my usb file but it got so far and said "install failed. OS X could not be installed on your computer. The installer encountered an error that caused the installer to fail. Contact the software manufacturer for assistance. Click restart to restart your computer and try installing again." I know it can run Mavericks as it was on it before I started. I have tried to install it a few times but I get the same error message, In the picture below there are 12 disks made that I think came from the usb instillation that I dont know what to do with, I dont know if I need the recovery partition but im hoping Mavericks will set that up in the install if I delete it with the command above. I read that the error im getting can be fixed by resizing the "Macintosh HD" partition just a bit smaller then trying the Mavericks install again but I havnt tried that yet. I cant delete the Macintosh HD partition in the non terminal diskutil either it says it cant unmount the disk and there is no option to unmount it, see picture below. I dont know what to do to get Mavericks back a solution will be greatly appreciated.

 

 

01.jpg

02.jpg

iMac

Posted on Aug 10, 2016 9:44 AM

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gabrielknight1

Q: diskutil cant erase disk in terminal Mavericks Install

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  • by macjack,

    macjack macjack Aug 10, 2016 10:00 AM in response to gabrielknight1
    Level 9 (55,668 points)
    Mac OS X
    Aug 10, 2016 10:00 AM in response to gabrielknight1

    Hi gabriel, the Recovery partition should not be affected if you choose your OS X formatted volume, "Macintosh HD.

    How much free space do you have in your internal disk?

    Also, if you are not using it from Recovery or another disk, you cannot unmount the disk you are working on.

  • by gabrielknight1,

    gabrielknight1 gabrielknight1 Aug 10, 2016 10:14 AM in response to macjack
    Level 1 (8 points)
    Mac OS X
    Aug 10, 2016 10:14 AM in response to macjack

    It should have the full amount for the Macintosh HD as I have done an erase on it and chose the format as Mac OS X Extended Journaled so about 630-something gig out of a 640 gig HDD.

     

    "Also, if you are not using it from Recovery or another disk, you cannot unmount the disk you are working on."

    Im using the "command + R" option when it boots is this the recovery you said about? If Command + R is recovery then im having the problem of not being able to delete and unmount the partition. 

  • by macjack,

    macjack macjack Aug 10, 2016 1:46 PM in response to gabrielknight1
    Level 9 (55,668 points)
    Mac OS X
    Aug 10, 2016 1:46 PM in response to gabrielknight1

    gabrielknight1 wrote:

     

    It should have the full amount for the Macintosh HD as I have done an erase on it and chose the format as Mac OS X Extended Journaled so about 630-something gig out of a 640 gig HDD.

    Ok that's great.

    gabrielknight1 wrote:

     

    Im using the "command + R" option when it boots is this the recovery you said about? If Command + R is recovery then im having the problem of not being able to delete and unmount the partition.

    Yes, command + r is recovery. Have you tried to force unmount it? Choose terminal. When you are in Terminal copy & paste this command at the prompt:

    diskutil list

    Press return.

    If it sees the disk, note the number of the disk (far left column) you want to mount.

     

    Then, enter this command:

    mount /dev/(number of disk)

    Put in the number no parenthesis.

    Press Return.

     

    To unmount use umount