You can boot from your usb drive and not have to download the macos installer again. Click browse button to import macos dmg file into the program.
The download can take some time depending on your internet connection.
Macos boot from usb. How to boot a mac from usb media getting your mac to load from a usb drive is fairly straightforward. Use the backup file to make a bootable usb drive. When the macos installer opens follow the onscreen instructions.
Startup manager if your mac won t boot up normally you can set it to boot from a different drive such as a usb stick containing macos installation files in bootable format. Click on your usb stick then select erase. Boot mac from usb drive using startup manager step 1.
Insert your formatted usb drive and click burn tab on the main screen. Select the volume containing the bootable installer then click continue. This will come in handy for fixing the macos could not be installed error.
Turn on your mac and continue to hold the power button until you see the startup options window which shows your bootable volumes and a gear icon labled options. Turn on your mac or restart your mac if it s already on. Make the format mac os extended journaled and use guid partition map as your scheme.
Right click on the installer file and click on show package. Simply plug your created usb drive into an open usb port on your mac. Now click on the erase button and the disk utility will prepare the usb stick for the next steps you re going to.
Insert the usb boot media into an open usb slot. Boot mac from usb option l. Power on the system or restart it if it s already on.
Press the power button to turn on your mac or restart your mac if it s already on. Leave the usb stick named as untitled. The latest versions of the mac operating system are only available through the app store.
Download the mac os x lion installer from the app store. Insert the usb boot media into a usb slot. The drive will have to contain a version of the os that is compatible with the mac.
Right click the software icon on desktop and select run as administrator from the contextual menu. Press and hold the option key immediately after you see the apple logo. And select the usb drive.
Holding that key gives you access to os.