DMG file is usually encrypted and compressed, unlike ISO, which is an uncompressed disk image format. When opened, it mounts a virtual disk on the computer, and is normally used for installing new applications. This boot drive has the latest macOS Catalina installer that does not have the 'Administrator' prompt many users are running into when installing, and certificates have been updated for all versions of macOS.Ī DMG file is essentially Apple's format for mountable disk images in Mac OS X (macOS) computers. Don’t need to spend time and bandwidth to re-download OS X Lion.Mac Os Boot Drive Usb Dmg Lion On Sierra By raiposriowei1975 Follow | PublicīRAND NEW USB Recovery Boot Drive with 5 IN 1 Mac OS-X/macOS recovery installers programmed on one USB drive, including the newly release macOS Catalina.

Though a recovery partition will be created when you install OS X Lion, a installation DVD or thunmb drive is good to have for “clean install” or new hard drive. Then you can boot into DVD or flash drive there. To use the OS X Lion DVD and USB flash drive, you press and hold “Option” key when you hear Mac startup chime at start up. How to boot into OS X Lion installer DVD or USB thumb drive Click “Restore” button to create your bootable OS X Lion thumb drive.After done formatting, click on the “Restore” tab, and choose the “InstallESD.dmg” file as “Source:” and your flash drive as the “Destination:”.Click “Apply” button to format your thumb drive (all data on the thumb drive will be erased).Click “Options…” button under the partition table and choose “GUID Partition Table”, so that the thumb drive is bootable.Under “Partition Information”, choose “Mac OS Extended (Journaled)” for “Format:”.Goto “Partition” tab and select “1 Partition” from the “Partition Layout” dropdown menu.Plug in your thumb drive and select it in the left-hand sidebar in Disk Utility.It takes more steps to make an OS X Lion thumb drive: Make offline OS X Lion installer flash drive Select the disk image (.dmg) in the Disk Utility’s sidebar, and click “Burn” button to start burning DVD.ĢB.Now, open “Disk Utility” app and drag the “InstallESD.dmg” file into the left-hand sidebar of Disk Utility.You will get a file called “InstallESD.dmg”. Open “Contents” folder, then “SharedSupport”. Right-click on the OS X installer and click “Show Package Contents”.

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