Making a Bootable USB Stick on an Apple Mac OS X from an ISO

This quick how-to will show you how to make a bootable USB stick from a downloaded ISO file using an Apple Mac OS X.

Note: this procedure requires an .img file that you will be required to create from the .iso file you download.

TIP: Drag and Drop a file from Finder to Terminal to ‘paste’ the full path without typing and risking type errors.

  1. Download the desired file
  2. Open the Terminal (in /Applications/Utilities/ or query Terminal in Spotlight)
  3. Convert the .iso file to .img using the convert option of hdiutil:
    hdiutil convert -format UDRW -o /path/to/target.img /path/to/source.iso)
  4. Note: OS X tends to put the .dmg ending on the output file automatically.
    Rename the file by typing:
    mv /path/to/target.img.dmg /path/to/target.img
  5. Run diskutil list to get the current list of devices
  6. Insert your flash media
  7. Run diskutil list again and determine the device node assigned to your flash media (e.g. /dev/disk2)
  8. Run diskutil unmountDisk /dev/diskN (replace N with the disk number from the last command; in the previous example, N would be 2)
  9. Execute sudo dd if=/path/to/downloaded.img of=/dev/rdiskN bs=1m (replace /path/to/downloaded.img with the path where the image file is located; for example, ./ubuntu.img or ./ubuntu.dmg).
    • Using /dev/rdisk instead of /dev/disk may be faster.
    • If you see the error dd: Invalid number '1m', you are using GNU dd. Use the same command but replace bs=1m with bs=1M.
    • If you see the error dd: /dev/diskN: Resource busy, make sure the disk is not in use. Start the ‘Disk’ and unmount (don’t eject) the drive.
  10. Run diskutil eject /dev/diskN and remove your flash media when the command completes
  11. Now the USB stick is ready. Boot the device that you want from the USB stick.
This entry was posted in Mac by djlaube. Bookmark the permalink.

About djlaube

I have over 16+ years of experience helping small to enterprise businesses nationwide design and then implement enterprise storage, backup and recovery, disaster recovery and system virtualization solutions including private cloud, public cloud and hybrid cloud infrastructures. I hold numerous storage and virtualization certifications. I have supported 18-25 sales reps at any one time as a presales engineer, involved in all stages of the sales cycle. I have consistently been a top producer in all of my roles. I have personally delivered over 300+ complex enterprise solution implementations from multiple vendors (including VMware, EMC, Dell, Symantec and HP). I am an expert in solution design and architecture and have designed over 250+ complex solutions for customers of all sizes (SMB to Fortune 100).

29 thoughts on “Making a Bootable USB Stick on an Apple Mac OS X from an ISO

  1. No need for that


    Run diskutil list to get the current list of devices

    Insert your flash media

    Run diskutil list again and determine the device node assigned to your flash media (e.g. /dev/disk2)


    Go to disk util with the media mounted right click on the left hand list
    and select “information”. Check the “disk identifier” entry.

    Great guide.

  2. It just doesn’t work wasted another 2 hours. Amazed that there is not a simple solution to make a bootable USB, been through 5 of these schemes and they fail. Comments support the idea that they do not work. I assume the lack of comments here is due to the author deleting any post that is not glowing

    • Your theory doesn’t hold water. Your comment is still here and the guide worked perfectly for me. All signs point to your inability to do it properly.

    • Put file you want to convert into desktop for ease.

      At step 3, enter info manually. All after qutation marks, “hdiutil convert ubuntu-12.10-desktop-amd64.iso -format UDRW -o ubuntu-12.10-desktop-amd64.img

      Basically, after the word convert and entering a space, drag iso file to terminal to auto fill address and after -o and another space, drag file again to terminal and change iso to .img or vice versa.

      After file is made, remove dmg at end and mac will ask you to confirm if you want to change file to just .img. Thats all.

      Hope it helps

      • hi,

        every time i try Step 3 it comes back with
        hdiutil: convert failed – No such file or directory
        do you know why that may be ?!
        I moved the file to my desktop and tired various names (i.e. simplifying the name to reduce chance of error)

        thank you

  3. It would be nice if you didn’t copy this verbatim from Ubuntu’s website. At least give some credit for stealing someone else’s tutorial. Sheesh.

  4. I think you have an unintended parentheses at the end of #3:
    “Convert the .iso file to .img using the convert option of hdiutil:
    hdiutil convert -format UDRW -o /path/to/target.img /path/to/source.iso)”

  5. hi, i have an issue, it works fine, but it requests my password, and 1. i dont have one, and 2. it doesnt allow me to type any passwords…
    could you help me please?

    • It’s not that it doesn’t allow you to type a password, but that it does not display anything as you type it. As for not knowing your password, I would try typing no password.

  6. not work for me ,
    i make all the steps, no errors , the usb have the files , but is not boot, not in mac not in other pc … is not bootable .. can anyone help me ?

    thank you

  7. Working on dd now, will see if it actually works. (“sudo dd if=/path/to/file | pv | of=/dev/diskN bs=1m” should give us all a count on progress instead of just flashing (for those lucky ones) usb stick |y|
    lolz on the GUI comments

    • I did try unitbootin for this testing matter but it is problematic for the purpose, I think maybe because the usb wasn’t unmounted, either way wasn’t a good option…

      begun the hdiutil convert process about 40mins ago, now burning img file to usb…

      it’s a bit slow but seems to work so thanks for everyone who wrote about this on several sites, this was the last one I arrived at so my message of thanks rests here!


  8. The easiest way to do this is with Disk Utilities. Use the “Convert” function to convert to the ISO file to a .dmg file, then restore the .dmg to the flash drive. Simple, no terminal window, no fuss.

  9. This guide worked for me.

    I wanted to create a windows build dvd from iso on my mac in order to rebuild a friends laptop.

    Thank you

  10. Thanks for the guide.

    I followed all the steps to create a bootable usb drive but it was not recognized when I booted with the “option” key held..

    Trying to update an Intel SSD but creating a boot drive for issdfut_2.0.9.iso.

    Please help!

  11. does anyone know I would get a permissions denied when I run the dd command? Below is the exact error.
    dd: /dev/rdisk2: Permission denied

  12. Probably won’t get an answer anytime soon, but i was wondering since there is no count or loading to show the progress, how long does usually take? Running on an i7 2.2 ghz processor and 16gb of ram

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