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Choose one image-writing method that is available on the computer you are using. You do not gain safety by writing the same USB with several tools in sequence. Each method below reads the completed Ubuntu ISO and overwrites the selected USB.
Option A: GNOME Disks on Ubuntu or Linux
Canonical recommends Disks when it is available. Ubuntu Desktop includes it, and many Linux systems using the GNOME desktop provide it too.
- Open Disks from the applications menu.
- Insert the USB and select it in the left sidebar.
- Verify its model and capacity. The internal system drive also appears in this sidebar, so do not choose by position alone.
- Close file-browser windows and applications that are using the USB.
- Open the drive menu marked with three vertical dots and choose Restore Disk Image….
- For Image to Restore, choose the completed Ubuntu Desktop ISO.
- Review the source image and destination device, then choose Start Restoring….
- Confirm the warning and enter the account password when the operating system requests administrator permission.
- Wait for the progress bar to finish, then choose Eject this disk.
“Restore” can sound as though it will recover old USB files. Here it means copying the image’s complete disk structure onto the target. Existing USB contents are overwritten.
Option B: Startup Disk Creator on Ubuntu
Startup Disk Creator is designed for Ubuntu images and Ubuntu-based distributions and is available on some Ubuntu systems. If it is not already available, use Disks above rather than installing several writers merely to complete the same job.
- Insert the USB and close any window displaying its files.
- Search applications for Startup Disk Creator.
- Check Source disc image. Use Other if the correct ISO was not found automatically.
- Check Disk to use against the USB model and capacity.
- Select Make Startup Disk.
- Read the destruction warning, confirm the exact USB, and continue.
- Wait until the application reports Installation Complete.
Do not use Startup Disk Creator as a general writer for unrelated operating systems. Its documented purpose is Ubuntu and Ubuntu-derived images.
Option C: balenaEtcher on macOS
Canonical’s current installation guide uses balenaEtcher for macOS.
- Insert the target USB.
- Download Etcher from its official site. Choose the macOS
arm64build for an Apple Silicon computer or the Intel macOS build for an Intel Mac. - Install and open Etcher.
- Choose Flash from file and select the Ubuntu ISO from Downloads.
- Choose Select target and select the exact USB.
- Choose Flash!, approve the macOS permission prompt, and wait for writing and validation to finish.
- Eject the USB safely.
An Apple Silicon Etcher build can write a USB, but that does not make the ordinary amd64 Ubuntu Desktop image a supported native installer for an Apple Silicon Mac. This series targets an Intel/AMD PC. The writer computer and the target computer can be different machines.
macOS may say the written disk is not readable. Do not initialize or erase it. Choose Eject. The Ubuntu image’s layout is not an ordinary macOS data volume.
Why ordinary file copying does not work
The ISO contains partitions, boot records, filesystems, and files in a defined layout. A file manager copies the ISO as one file onto an existing filesystem. An image writer replaces the USB’s layout with the image’s layout. Only the second operation creates the expected installation media.
An advanced note about dd
Linux and macOS include the command-line dd tool, and Canonical documents it as an advanced method. It is intentionally not part of this beginner procedure. dd writes directly to a device and gives little protection against selecting the internal system disk as its output. One wrong device name can destroy the running system.
Use the official bootable USB documentation if a graphical writer is unavailable and an experienced administrator will verify the device. Do not copy a dd command containing somebody else’s /dev/sdX name.
Common mistakes and recovery
The ISO was dragged to the USB. Recreate the media with one of the image writers above.
The source and target were reversed. Cancel before confirming. The ISO is a file; the USB is the device that may be erased.
The target is reported as busy. Close file browsers and applications using it, then eject and reconnect the USB. Do not force a write while the target is still unclear.
The writer reports success but the computer will not boot it. Do not keep rewriting with random tools. Use the symptom checks in Lesson 2.3.
The operating system asks to initialize or format the result. Cancel and eject. That prompt often means the host does not understand every partition on valid installation media.
Practice
Knowledge check
Name the source and target before writing: the source is the completed Ubuntu ISO file; the target is the exact USB whose current contents will be destroyed. If you cannot state the target’s model and approximate capacity, stop.
What to learn next
When the writer reports success, continue to Boot Ubuntu from a USB Drive. Use Ubuntu USB Not Booting? Use These Safe Checks if it is missing or fails before the installer appears.