sudo /Applications/Install\ macOS\ Sonoma.app/Contents/Resources/createinstallmedia --volume /Volumes/USB
After creation, test the USB:
A .dmg is a disk image, not the installer itself. Double-click the .dmg file to mount it. Inside, you will usually find the actual app (e.g., Install macOS Monterey.app ). For the Terminal command to work, this app must be moved into your folder. 3. Use the 'createinstallmedia' Command create mac os x bootable usb installer from dmg