Ask Ubuntu is a question and answer site for Ubuntu users and developers. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I have a Macbookpro and I'm planning to create a multiple boot. I've already created the necessary partitions and downloaded image file (i386)

When I try to create a bootable USB stick from the ISO file, by means of "recovering" the disk image into the USB drive using Disk Image Utility, I get the following message:

Could not validate source - corrupt image

The disk image can't be mounted in OSX either, I also get a similar message.

Is there any way to make a bootable Ubuntu USB stick from an ISO image in OSX?


share|improve this question
On step number 4 <br> sudo dd if=/path/to/downloaded.img of=/dev/rdiskN bs=1m I entered the path and the it says no such file or directory.<br> How can I enter the correct path? Could you give me some example about the path? <br> Thanks – user269489 Apr 16 '14 at 11:07
Here are the official directions for this will which likely be kept up to date: – billynoah Aug 2 '15 at 2:20

The problem you're having is that is file you downloaded is corrupted, hence, not useful.

To solve this, download Ubuntu again. Once done, try again. You can follow the Official Guide for OSX:

1: Download Ubuntu

2: Convert the ISO file

Convert the .iso file to .img using the convert option of hdiutil

hdiutil convert -format UDRW -o ~/path/to/target.img ~/path/to/ubuntu.iso

Note: OS X tends to put the .img ending on the output file automatically.

3: Determine the media to install

Run diskutil list to get the current devices. Insert your USB and the run again diskutil list. The new device its your USB.

4: Install into the USB

Unmount your device (not physically) with diskutil unmountDisk /dev/diskN where N is your USB number and execute

sudo dd if=/path/to/downloaded.img of=/dev/rdiskN bs=1m


  • 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

5: Eject

Run diskutil eject /dev/diskN and remove your flash media when the command completes.

6: Boot

Restart your Mac and press alt/option key while the Mac is restarting to choose the USB stick.

share|improve this answer
Typo that's already fixed in the original doc: OS X tends to put the .img ending -> OS X tends to put the .dmg ending – Victor Sergienko Jan 18 at 10:12

Step 4 needs to change:

unmountDisk /dev/diskN

should now be:

diskutil unmountDisk /dev/diskN

For reference, see, as this is what worked for me where as the instructions above did not. Using OSX v. 10.8.2

share|improve this answer

It is very difficult to run ubuntu from a USB stick on a Mac. Here are some options:

  1. Run Ubuntu from a USB stick on a PC
  2. Install Ubuntu on a PC
  3. Install Ubuntu on a Hard Drive on OSX.

But for booting Ubuntu on USB I have not succeeded in doing so.

share|improve this answer
It is very possible. If you make a USB flash drive with Unetbootin, typically it is only bootable on a PC. If you make it with the technique on the website, it generally works fine. If you think I am mistaken, can you edit your question to provide more information? – Eliah Kagan Feb 4 '13 at 21:29

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.