Following on from my post about making a bootable 10.7 Lion Install DVD, here's how to make a bootable USB flash drive.
You will need the following: -
- A Mac
- A copy of the Lion Installer App (available from the AppStore)
- A USB Flash Drive / Pen Drive with 4.2GB (approx) of free space
** NOTE ** Unfortunately, this doesn't appear to quite fit on a 4GB Pen Drive, you may find differently but for me Disk Utility gave a 'Not enough space error' Anything above (eg. 8gb) should be fine.
1 - Go to the Applications folder and right click (or Control-Click) on 'Install Mac OS X Lion' and select 'Show package contents'.
2 - Navigate to the Contents > SharedSupport folder
3 - Copy InstallESD.dmg to someplace (eg. your Desktop)
4 - Open Utilities > Disk Utility.app and click on your USB drive in the left pane. Then click 'Partition'.
5 - Enter a name for the partition and make sure the format is set to 'Mac OS Extended (Journaled)'.
6 - Click 'Options' and choose 'GUID Partition Table' as the partioning scheme.
7 - Click OK, then Apply, you will then have to confirm and authenticate you want to go ahead. This will erase all data on your Flash drive!
8 - Now click the restore tab, select (or drag) the copy of InstallESD.dmg you made earlier in the 'Source' box.
9 - Drag your USB Flash drive in to the 'Destination' box and click Restore, again you may have to authenticate.
10 - After a few minutes your USB Drive will be ready to do... How long really depends on the speed of your USB Drive, but most have faster Read speeds than Write and you only have to write it once.
11 - To test your USB drive, you can either go to system prefrences > startup disk and select it there, then hit restart, or just hold down the Option / Alt key while you restart your computer.
12 - Enjoy some peace of mind!
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