A specialized utility for downloading macOS firmwares and installers. Download Mist from GitHub .

Your Mac is either too old (pre-2012) or too new (2019+ with T2 chip). Mojave does not support Macs released after 2019. Apple Silicon Macs cannot run Mojave at all.

sudo /Applications/Install\ macOS\ Mojave.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume