I recommend erasing the destination, so be sure to backup any data on the thumbdrive prior to this step! This will take a few minutes to do. (ie THUMBDRIVE in the screenshot) and then click Restore Once you have it chosen, click and drag your USB Thumbdrive from the left pane to the Destination box. Click on the Browse button and locate the. On the right pane, go to the Restore tab.ģ. This is very handy for us Macbook Air users that do not have an external optical drive.ġ. We can then boot the USB Drive on our Mac to install OS X Lion from it. dmg installer file for OS X Lion onto a usb thumbdrive. – USB Thumbdrive or Memorycard Reader w/memory card (4GB mininum, data will be destroyed).– Mac running OS X Leopard or Snow Leopard.– OS X Lion installation DMG (hint: file named: mac_os_x_10_7_11a390.dmg).

We will need a copy of the installer dmg (not provided) and a 4GB USB Thumbdrive or Memorycard Reader w/memory card and a Mac to convert the dmg to a bootable usb thumb drive. This recipe will explain how to make a USB Thumb Drive bootable with the OS X Lion Developer Preview installer on it and in turn allow you to install Lion on a Mac without an optical drive (ie Macbook Air line).

Mac disk image thumb drive