i am trying to install ubuntiu as duall boot but balena do not give the right to install on my main disk
Hello, Etcher is designed to image entire drives - probably not what you want to use on your main drive for setting up dual boot. However you could use Etcher to make a bootable USB drive that can be used to set up dual booting. (Check out the many fine tutorials for setting up dual booting online) By the way, you actually should be able to select your main drive (again, not recommended) by clicking the link in the UI that reads “show 2 hidden” or similar wording.