Create Mac Os X Bootable Usb Installer — From Dmg

First, you need a USB flash drive with at least of space. Before moving the installer, the drive must be formatted to a scheme the Mac can read during the boot process. Plug in the drive and open Disk Utility . Select the USB drive from the sidebar and click Erase .

What if your DMG does not contain a .app file, but rather a InstallOS.pkg or MacOSInstaller.pkg ? create mac os x bootable usb installer from dmg

For very old OS X installers (e.g., Lion, Mountain Lion), you may need to use a different method or restore the .dmg directly via Disk Utility's Restore feature. First, you need a USB flash drive with at least of space

Unmount the USB drive: