| Requirement | Specification | |--------------|----------------| | | 16 GB or larger (32 GB recommended for modern macOS versions) | | DMG File | Contains the full macOS installer (e.g., Install_macOS_XXX.dmg ) | | Host Mac | Any Mac running macOS 10.12 or newer | | Backup | All data on the USB drive will be erased |
: Double-click your source DMG file so it appears in the Disk Utility sidebar. Restore the Image : Select your newly formatted USB partition from the sidebar. Click the Restore button in the top toolbar.
Modern versions of the macOS bootable creator tool require an .app file structure rather than a raw disk image. If your DMG contains the actual installer application inside it, you must extract it first. Double-click your macOS .dmg file to mount it. Look inside the mounted virtual disk.
If your DMG is a raw sector-by-sector copy of an already bootable disk image (and does not contain an .app installer wrapper), the Terminal script method will fail. In this rare scenario, you can flash the image directly using a third-party tool like . Download and install BalenaEtcher (free and open-source). Insert your formatted USB drive.
How to Create a Mac OS X Bootable USB Installer from a DMG File create mac os x bootable usb installer from dmg
hdiutil convert /path/to/installer.dmg -format UDRW -o /path/to/installer.img
Plug the newly created bootable USB drive into a high-speed USB port.
Creating a bootable USB installer from a macOS requires specific steps because a standard DMG is a disk image, not a raw bootable drive sector. While newer versions of macOS utilize .app installers from the Mac App Store, older versions like Mac OS X Lion, Mountain Lion, Yosemite, or El Capitan are frequently distributed as DMG files.
If you are on a Windows PC and have a macOS DMG, you can use third-party tools to write the image to a USB drive. Modern versions of the macOS bootable creator tool
Verify the name of the installer application in your /Applications folder matches the command you are typing.
Double-click your .dmg file to mount it. It will appear on your desktop or in the Finder sidebar.
Method 2: The Disk Utility Method (For Legacy OS X Versions)
To verify from Terminal:
Creating a bootable USB installer for macOS from a DMG file is an essential skill for Mac users, allowing for clean installations, upgrading older systems, or troubleshooting.
Right-click the TransMac shortcut and select . Insert your USB drive into the PC.
Before diving into the step-by-step methods, ensure you have the following components ready:
The process takes 15–30 minutes. Once you see Copy complete and Done. , your bootable USB is ready. Look inside the mounted virtual disk