How to Burn an ISO File to a USB Drive

Get a step closer to installing Linux

UNetbootin on Ubuntu Linux desktop

Installing the Linux operating system is a fairly straightforward process. The first step is downloading an ISO image, also called an ISO file. An ISO file contains everything necessary to install and boot Linux. But you can't simply copy an ISO file to a USB flash drive and then boot up your new Linux OS. Instead, you must burn the ISO image to the drive so that it's bootable.

We'll explain how to burn an ISO file to a USB flash drive with the help of a user-friendly tool called UNetbootin, which is available for Windows, macOS, and Linux. You’ll need a USB flash drive with at least 8GB of free space, an ISO image of the distribution you want to install, and a desktop or laptop computer.

UNetbootin allows you to create bootable USB drives for Ubuntu and other Linux distributions without burning a CD. UNetbootin will download one of many supported Linux distributions, or you can supply your own Linux .iso file.

In this tutorial, we're using UNetbootin with Pop!_OS, a version of Linux created by System76. Regardless of what Linux version you use, these instructions will be very similar.

Download an ISO File

The first step is to download the ISO image of the Linux distribution you want to try. For example, to download Ubuntu Linux, go to the Ubuntu Desktop download page and download the image file, which will end in .iso. ISO files are typically large, up to 4GB, but are usually less than 1GB.

Install UNetbootin

The UNetbootin application doesn’t install. Instead, it’s an executable file, which means you download the file and then run it. If you're using Windows or macOS, simply double-click on the downloaded file to run UNetbootin.

Some distributions of Linux may show a grey window when launching UNetbootin. One way to work around this is to issue the following as a command in Terminal:

sudo QT_X11_NO_MITSHM=1 unetbootin

Burn an ISO Image

To burn your downloaded image file, launch UNetbootin and follow these steps:

  1. From the UNetbootin window, select the radio button for Diskimage and then press the file button (three horizontal dots).

    Screenshot of the main Unetbootin window.
  2. Locate the downloaded ISO file, select it, and press Open.

    Screenshot of selecting the ISO to burn.
  3. Insert your USB drive into the computer you're using to run UNetbootin.

  4. From the Type drop-down select USB Drive, and from the Drive drop-down select the USB drive you just inserted.

    Screenshot of selecting the target USB drive.
  5. Select OK and, when prompted, press Exit.

At this point, depending on the speed of your computer and the size of the distribution you’ve downloaded, UNetbootin will take some time to burn the ISO image to the USB drive. When it completes, close UNetbootin, remove the USB drive from your computer, insert the USB drive into the machine on which you're installing Linux, boot the machine, and then begin the installation process.

To boot from the USB drive, you must know how to access your computer’s Boot menu. This depends on your computer. To find out, search your computer's make and model in Google with the keywords "boot menu.” For instance, if you have a System76 Thelio, search “how to access System76 Thelio boot menu.”