Install OS X from DMG File

   Posted October 10, 2007 by David Kirk in Apple Mac

Installing OS X from a DMG file can be difficult. With leopard testing and development, many people are having troubles installing from the supplied binary. Here is how it can be accomplished.

Installing OS X from a dmg file format instead of a DVD/CD format seems challenging. Here is how it can be accomplished.

1. Burn it to Dual Layer DVD

OS X is too large to fit on a single layer DVD; however, many macbooks support burning dual layer DVDs. The media is expensive, but for many people this is the easiest option.

Burn it and reboot to it. The OS X will install.

2. Restore the dmg file to an external device

An external hard drive or an iPod in hard disk mode will serve as an excellent booting device as well.

– Copy your dmg file to your current apple desktop.
– In the Utilities Folder in your Applications Folder select Disk Utility
– Select your external device in the left column of the utility
– Click the Restore button
– Drag your dmg to your Source textbox
– Drag your device from the left column to the Destination textbox
– Click the Restore

You will lose any information you have in your external device in this process. After the dmg is restored to the external device, change your boot disk to this device and reboot.

Dragging the source and destination files can be a little confusing. Click the picture below for a larger version.


About David Kirk

David Kirk is one of the original founders of tech-recipes and is currently serving as editor-in-chief. Not only has he been crafting tutorials for over ten years, but in his other life he also enjoys taking care of critically ill patients as an ICU physician.
View more articles by David Kirk

The Conversation

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  • Alessandro

    Thank you very much… ehm It’s true: nobody think to the simplest things! šŸ™‚

  • ali

    you said that i must Copy my dmg file to my current apple desktop , but what i must do if my disk was formated

    • You will have to use another computer to either burn the dmg to a DVD or an external hard drive.

  • Nick

    Iā€™m having a bit of a problem, maybe you will be able to help.

    I have two hdds installed and a dmg of leopard.

    I go into the disk utility, and try to use the restore feature with no luck.

    I get either an error one, or an error 16, both telling me the copy failed.

    Today, I purchased a 500gb firewire drive to try to get it to work. No luck, same error.

    When I try to do the same think on my macbook, (I am trying to install leopard on my powermac running osx 10.3 )
    When I do it on my macbook, it begins to copy files, and works for several minutes, and then I get an error stating: could not restore, operation not supported.

    What am I doing wrong? Any insight?

    I have a dl burner available to me.

    I have my original osx leopard install disks that came with my macbook.

    Any suggestions?

    • Anonymous

      Sounds like your DMG of leopard is corrupted.

    • Jerome

      The error 16 will go away if you click Images -> Scan Image for Restore… and pick the .dmg file. After the scan completes successfully, there won’t be a problem.

    • T

      Sounds like an external 2.5″ HD from Western Digital. Had similar problems.
      Their PCB that converts FW to IDE is done poorly (power supply not enough).

      br T

  • Ryan

    Hey, I have a question.

    If I restore the dmg to an external device, will I still be able to use that device? I mean, will it be able to do it’s intended purpose once this is all said and done?

    I’m only asking because I was going to use my digital 8-track recorder as the device, but I want to still be able to record my music with it after. Restoring a dmg to it isn’t going to make it inoperable afterwards, will it?

    Thanks for any help

    • James

      I think you can later use the erase in disk utlity to reformat it again

  • Anonymous

    plz send me how i can dow dmg to osx fils

  • Anonymous

    You may need to use HTS (Mac OS) file system format for this to work. I tried using FAT and had errors. Then obviously realized that FAT cannot support files over 2GB. I reformatted to HTS and rock on….

  • Something different when restoring the Snow Leopard DMG to a flash disk.

    You need to mount the dmg 1st, then use disk utility to restore the actual Mac OS X Install DVD (inside the DMG) to the flash disk, instead of specifying the DMG as source.

    Then the 8G USB flash disk is loaded with Snow Leopard bootable, I think it’s just UNIX command dd? Keep pressing option key until you see the option to choose the boot device;-)

    • InDaWild

      The program that does it is named “diskimages-helper”, not “dd”. I guessed it was “dd” myself, but after I examined the process a bit, I saw that it’s not šŸ™‚

      It’s good to know that restoring to a USB Flash Drive will take more time, so be patient!

      Thanks for the tip – I, like many others, couldn’t see the obvious…

  • Anonymous

    Hi im having a slightly different problem for the DL DVD way of installation. i have 10a432 and i have burned it to a DL DVD using 2.5x speed. the installer turns up perfectly and goes up to 20% but then tries to restart and reboot and thats when i end up with a screen with a “?” flashing in the middle. i have tried booting using the alt key but i cant see my DVD in the boot device list. i have checked with my leopard disk and it does boot from that DVD. any ideas?

    • Geozuniga123

      hey u need a program called atoski it works and also installs mac osx 10.5

  • karthi15

    im using windows 7.i’m eager to try snow leopard.can i install it with 7 as a dual boot………..

  • South097

    so my disc drive is shot anyway i can use toast as an alternative?

  • Castaneda

    error in the .dmg file, and the system is restarting all over again endedless

  • Nick Paton

    Can some one please tell me how to install leopard on a os x 10.3.9 iMac G5 system from a 8gb 2.0 USB?

    • Roland Anderson

      Yeah – Follow his instructions exactly.Ā 

  • Guest

    how did you format your USB HD ?
    In Disk utility go to partition then by options change to guid-partition.

    (sorry for my bad english)

  • marky mark

    Hey I’m trying to restore the .dmg file so i can boot from a usb external HD.

    My problem is i recieve an error (16) when trying this?!?! im not really sure what this means and how i can get passed it. im running a mackbook with 2GB memory. Im wondering if my file is corrupt or is this a problem with disk utility? any advice on this situation would be a great help. Also my cd drive isn’t working, this is why i need to beet from an external HD.

    Thanks! – Mark

  • al

    you need to format the usb drive to a mac format and then follow the instructions listed above.

  • klaus

    Thank you for your help, it’s a nice tuto !
    btw, you can also do it on a usb stick, not only HD (i’ve done on it on a usb, it’s working).

  • Eeyore

    Thank you! This is exactly what I needed and it worked perfectly.

  • sam

    Would this method work with a USB stick instead of a hard drive?

  • Danny Biz

    Hey Guys,

    I have a macbook (old Version) now running Windows 7 Ultimate. I want to install a Mac Os X Snow Leopard of Lion.

    I have the two dmg Mac Os X ( Snow Leopard and Lion) but I have tried either to burn or run them on my macbook which is running now Windows 7 and I failed.

    What can I do? both dmg files are single to mean 1 file of Snow Leo (7.3 GB) and Lion (4.21 GB). I have tried to bur them using disk utility but I failed and I wonder if there is a way to run it from Windows or create a bootable disc with Windows.

    What can I do? Help please!


    • krish

      > bro i am also wanting same help can anyone help us two out??

  • krish

    i want to install mac os x lion in my hp laptop which currently have win 7 .I have a .dmg operating system file and want it to make bootable from usb using win can i make my usb bootable??

    what should i do to fix my problem?
    help me please!!!

  • sercan

    thank you its was helpful

  • sercan

    awesome thank you i manage to transfer it

  • Stefanos

    Your guide is quite simple and thanx for the effort, but I have a problem and I would appreciate if anybody could help.

    In the step “ā€“ Drag your device from the left column to the Destination textbox” I just can’t drag any device from the available ones in the list to the Destination textbox because it is greyed out, i.e. doesn’t allow you to go further. I tried to google any possible answers but nothing of use came out.

    Any sort of help would be hugely appreciated as I’m stuck on Tiger.

    Thanx again for your guide!
    Stefanos, Greece
    MB-13″-2007, 2.16GHz Intel Core 2 Duo, Tiger 10.4.11

  • Trim

    This worked perfectly well ! thanks a lot, i used a usb stick šŸ™‚
    now just tell me, how do i revert the usb so i can use it normally again? please reply?

  • mitts

    Successfully Upgraded from OS 10.5.8 to 10.6.3 (3 years late…)

    To be able to copy the 6 gb .dmg file onto USB drive and use it as a startup disc, be sure to use disc utility to partition the USB drive so that it reads “Partition Map Scheme: GUID Partition Table”

    Then Format the Volume to a Mac OS Extended format

    Finally copy the .dmg to the USB drive, restart the computer holding down option key and select USB drive as startup disc. Installer begins automatically

  • Blake Wood

    i am getting this error…what do i do

    Could not validate source – Invalid argument