balenaEtcher is a free, open-source application for writing operating-system images to SD cards and USB drives on Windows, macOS and Linux. It transfers an existing image to removable media and checks the written data, with a graphical workflow for selecting the image, choosing its destination and starting the flash.
Image writing
Etcher copies an image byte for byte onto the selected drive. The image supplies the disk layout and contents; the program writes those contents without changing them to suit a different operating system. This makes balenaEtcher useful for preparing media from ready-made system images, including Linux images intended to boot from USB.
The input can be an uncompressed image or a compressed image in formats such as ZIP, GZ, XZ and Bzip2. Etcher handles the compressed input during flashing, so a separate extraction stage is unnecessary for supported images. The destination needs room for the expanded image, rather than just the smaller archive file. DMG images are also supported.
Drive selection and validation
The destination selector controls which connected drive receives the image. System drives are hidden by default, while warnings identify problems such as a locked SD card or a target too small for the image. Flashing replaces data on the selected destination; it is a disk-writing operation, not a file copy into an existing folder.
After writing, balenaEtcher can validate the transferred data to check that the image was written correctly. Another image can be flashed without closing and reopening the application.
Boot images
Bootability depends on the source image. Etcher preserves what it receives and does not perform the extra preparation required by Windows installation images. Ubuntu images designed for direct USB writing fit Etcher’s byte-copy approach.
For live Linux media, balenaEtcher does not configure persistent storage. It can write the supplied system image, but it has no control for adding a separate area that retains a live session’s files and settings across restarts.
