HOWTO – Clone your Mac OS X hard drive

May 22nd, 2008 at 12:16 · Filed Under Call Me a Geek, Computing, HOWTO, Mac OS X 

First of all, why do I need to clone the hard drive? Good question though. Here are a few possible answers:

  1. I have too much money to spend for a spare hard drive to clone my Mac hard drive.
  2. I want to have a bootable external hard drive, installing on an external USB hard drive is not possible.
  3. I want to upgrade my Mac’s hard drive, and I don’t want to do the installations and setup all over again

Obviously number 3 is my answer. I acquired a bigger capacity hard drive to upgrade my current 120GB hard drive in my MacBook. After some Googling around, I found an answer.

There is an Apple utility program called Apple restore or asr located in /usr/sbin. Connect your external USB hard drive and format it using Disk Utility. Open the Terminal in Applications -> Utilities. Type the following command line into the Terminal to copy your hard drive over your external drive.

% sudo asr -source /Volumes/OSX BOOT VOLUME NAME/ -target /Volumes/TARGET VOLUME NAME/

Replace “OSX BOOT VOLUME NAME” and “TARGET VOLUME NAME” with actual volume names. asr will take quite some time to copy the contents of hard drive to external hard drive. Get a cuppa, pop in your iPod earphone and relax.

When asr completes the execution, it will print a message:

asr: did not copy blessed information to target, which may have missing or out-of-date blessed folder information.

Then, bless your target drive with this:

% sudo bless -folder /Volumes/TARGET VOLUME NAME/System/Library/CoreServices

Now, the hard drive is bootable. Restart your Mac and hold down “option” key. A screen will appear allowing to choose which volume to boot from.

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Comments

18 Responses to “HOWTO – Clone your Mac OS X hard drive”

  • Jonathan Collins on May 25th, 2008 18:55 1

    Adrian, thanks for tips. I am a brand new Mac user (couple of days old) and your blog has provided a lot of useful information about using a Mac.

    Jon C.

  • dragon on June 27th, 2008 16:54 2

    Thanks bro, you saved my day. I don’t have to search the web for how to clone my hard disk.

    I bought a new 250GB drive to upgrade my new MacBook. Yes, I upgraded to a new MacBook 2.4GHz. I wanted to clone my “old” hard disk so that I could install Tiger on the old hard disk and had Leopard on my new hard disk. I wanted to be able to boot from my old hard disk (Tiger) from USB. And this has saved me a lot of time. This method also lets me test the newly cloned hard disk before I swapped the hard drive.

    龙

  • Ranjit on June 29th, 2008 9:17 3

    Hi,

    Thanks for the tips. Nice blog too.

  • Tokyo Mac on July 5th, 2008 9:19 4

    Very useful, thankyou. As fyi to others, my source and target volumes have spaces in the name, which I have to “escape” with the backslash. I.e.,

    % sudo asr --source /Volumes/OSX\ BOOT\ VOLUME\ NAME/ --target /Volumes/TARGET\ VOLUME\ NAME/

    ( MacOS 10.5.4, Power PC )

  • Tokyo Mac on July 5th, 2008 9:21 5

    sorry, I am in Japan .. the keyboard “backslash” appears as a yen symbol online – please edit this comment !

  • Adrian Hoe on July 5th, 2008 12:27 6

    Thank you Tokyo Mac.

  • Ben Ford on November 5th, 2008 1:53 7

    From the manpage:

    –updatebless When performing a non-erase restore,
    –updatebless will update the appropriate
    information required for the restored volume to
    boot if the source image is bootable (equiva-
    lent to sudo bless –mount –setBoot).

  • Joshua on November 5th, 2008 2:00 8

    Filenames with spaces may also be enclosed in single quote marks on the command line. For example,

    % sudo asr –source ‘/Volumes/OSX BOOT VOLUME NAME/’ –target ‘/Volumes/TARGET VOLUME NAME/’

    Hopefully that displays correctly in all languages !

  • hauns on February 13th, 2009 16:32 9

    great tip.

    however, what is wrong using disk utility.app’s restore functionality? is it because for disk utility route one needs to boot from a system disk and for this method you can work off the local disk (that needs to be cloned)?

  • Adrian Hoe on February 13th, 2009 21:33 10

    Hauns,

    There are a number of reason to clone your hard disk. First reason will be the upgrading of your hard disk. By cloning your hard disk, you get an exact replica of your old bootable Mac volume and all the applications and data onto your new hard disk.

    Second reason is you want to have entire hard disk backup; your bootable volume, applications and data. So when your hard disk fails, just plugin the new one and off you go.

    The list goes on as far as your creativity can go.

  • Tan Yock Pon on February 15th, 2009 21:29 11

    Adrian,
    Does that mean I can use your cloned USB Hard Disk on the PC also?I am getting to know Hackintosh.Are you free to help my school, SJKC TING HWA 3351432 to start a Homepage.We will be able to pay some coffee money.I lost your number,sensei.
    Tan Yock Pon 15-02-2009

  • Mary on February 17th, 2009 22:25 12

    Why don’t you just use Restore from Disk Utility? It’s built right into the OS and doesn’t require getting a text string typed in correctly to work?

  • orbosphere on March 10th, 2009 9:00 13

    Thanks a ton, this got me out of a jam twice now.

  • Adonis on November 7th, 2009 4:52 14

    Actually the Restore function of Disk Utility (as Mary mentioned) uses asr under the hood. Thus you can simply use that. (It also has the erase option which as pointed out will automatically bless a copied volume/image. The only “gotcha” is that you CANNOT copy/restore, with asr or Disk Utility, an entire drive, but only a volume at a time).

  • Jeremy on December 29th, 2009 19:06 15

    Hi Adrian
    My problem is slightly different. I got my hard disk upgraded to a 500GB from a 120GB, and got my previous OS cloned over. However, the OS doesn’t recognise that I’ve got 500GB, and only recognises 120GB. Disk Utility does recognise it, but I am unable to partition it or do anything with the other free space, getting “MediaKit reports partition (map) too small” as the response. Thanks for any advice you can give!

  • Adrian Hoe on December 29th, 2009 19:46 16

    Hi Jeremy,

    This is strange. Which version is your OS?

  • Jeremy on December 30th, 2009 18:32 17

    It’s the Snow Leopard 10.6.2.

  • Adrian Hoe on December 30th, 2009 19:13 18

    Jeremy,

    I am sorry because for some reasons I am still using Leopard. This could be a bug of some sort. Perhaps you should try Apple’s forum.

    If you have found a solution, please share it here.

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