Creating a bootable macOS USB installer from a DMG file involves using the createinstallmedia
| Symptom | Diagnosis | Fix |
| :--- | :--- | :--- |
| createinstallmedia not found | You pointed to the wrong path or the app is damaged. | Ensure the .app is in /Applications and you typed the name exactly (use Tab key for autocomplete in Terminal). |
| "Not enough space" | Your USB is smaller than 12GB or corrupted. | Use a 16GB+ drive. Re-format using Disk Utility (View > Show All Devices > Erase with GUID). |
| USB doesn't boot | The DMG was for a different architecture. | A DMG for a PowerPC G5 won't boot an Intel Mac. A Catalina DMG won't boot a 2008 MacBook. Check compatibility. | create mac os x bootable usb installer from dmg
(Replace "Sonoma" with your actual OS name, e.g., "Ventura", "Monterey", or "Big Sur") Creating a bootable macOS USB installer from a
USB Flash Drive: At least 16GB or larger. The process will erase all existing data. USB Flash Drive: At least 16GB or larger