The process of creating a bootable macOS USB installer from a DMG file is a critical skill for system recovery, hardware testing, or managing multiple Apple devices. While Apple's official "createinstallmedia" method is the standard, starting from a raw DMG file—especially when working on a non-functioning Mac or a Windows PC—requires specific technical steps to ensure the final drive is actually recognized by the Mac's firmware. 1. Prerequisites and Initial Preparation
sudo /Applications/Install\ macOS\ [Version\ Name].app/Contents/Resources/createinstallmedia --volume /Volumes/USB
Drag the .app file to your Applications folder. (The Terminal commands rely on this default location). create mac os x bootable usb installer from dmg
The workaround:
Install macOS [Version].