Drag the formatted USB key to the “Destination” and check “Erase destination”.This is why we mounted the InstallESD.dmg file earlier, because we can just drag and drop the “Mac OS X Install ESD” image into the “Source” – if you didn’t mount the image, you can manually locate and select the image file yourself by clicking on “Image” Now you need to set the source disk for the restore.Right-click on the USB drive in Disk Utility and select “Restore”.Now that the USB flash drive has been formatted to the appropriate filesystem, we are going to restore the previously mounted InstallESD.dmg file to the blank USB drive. Click on “Erase” to format the USB drive.Choose “Mac OS Extended (Journaled)” as the Format, and name the USB key what you want.Select your USB drive from the left side of Disk Utility, then click on the “Erase” tab.Next, we format the USB flash drive, this will become the bootable Lion installer: Double-click on “InstallESD.dmg” to mount the Lion disk image onto your Mac desktop, it will show up like the image below.

Open the “Contents” directory and then go into “SharedSupport”.Right-click (or control-click) on the “Install Mac OS X Lion.app” and select “Show Package Contents”.If you have anything stored on the USB flash drive you’re going to lose it, so be prepared for that and back it up.įirst we are going to locate the Lion InstallESD.dmg file and mount it: We’re going to assume you already have Mac OS X Lion downloaded from the App Store, if you don’t, do that first. How to Create a Bootable Mac OS X Lion Installation USB Drive Download Mac OS X Lion from the Mac App Store ($29.99).8GB+ USB flash key drive, these are cheap and ubiquitous on.A Mac with Mac OS X 10.6.8 so you can download and access Lion.

This is pretty easy to do, but I have made the walkthrough as simple as possible with plenty of screenshots, so just follow along the instructions.

Mac os x mountain lion install disk