So, in my case, the above command becomes: diskutil unmountDisk /dev/disk2 Where N is the device number for the USB you got previously. When you got the disk number, run the following command: diskutil unmountDisk /dev/diskN So for me, the command is like this: hdiutil convert -format UDRW -o ~/Downloads/ubuntu-14.10-desktop-amd64 ~/Downloads/ Normally the downloaded file should be in ~/Downloads directory. Open a terminal, either from Launchpad or from the Spotlight, and then use the following command to convert the ISO to IMG format: hdiutil convert -format UDRW -o ~/Path-to-IMG-file ~/Path-to-ISO-file This can be easily done using hdiutil command tool. The file you downloaded is in ISO format but we need it to be in IMG format. Ubuntu 14.04 is the latest LTS version, and this is what I would recommend to you. Since you are using a Macbook Air, I suggest you to download the 64 Bit version of whichever version you want. Jump to Ubuntu website to download your favorite Ubuntu desktop OS. Of course, you need to download ISO image of Ubuntu desktop. Of course hit the Partition button to format the USB drive. It will give you a warning message about formatting the USB drive. When all is set to go, just hit the Apply button. You’ll find the latest Ubuntu releases under the download section. The first step is to download the ISO of Ubuntu or whichever Linux you want to use. Step 1: Download the ISO image of Ubuntu Linux All you need to do is to download Linux ISO, download Etcher, plugin the USB and hit the flash button. Trust me, the Etcher tool makes live USB creation a painless task. Method 1: Create live Ubuntu USB in macOS with Etcher Let’s start with the graphical method first. I am using Ubuntu in this tutorial but it should work for other Linux distributions as well. Internet connection for downloading Linux ISO and tools.A USB key (pen drive) of at least 4 GB in size.I’ll also tell you how to boot from a live Linux USB on a MacBook. I am going to show you two ways of creating a live Linux USB in macOS:

You have got a Macbook and want to install Ubuntu on it or perhaps on some other system.

Bootable flash drive mac