When upgrading a Mac to Apple’s OS X Lion the new no-box-or-cd install left me searching for directions on how to do a fresh install instead of an upgrade. By default OS X Lion upgrades from Snow Leopard potentially leaving old OS cruft laying around.
Install Mac OS X Lion App, which is what Apple gives you when you purchase Lion from the App Store, can be used to create a bootable DVD or USB drive. To create this copy the
InstallESD.dmg file, from the
Install Mac OS X Lion Package, onto a DVD or USB drive as this post describes. You can then boot off of the USB/DVD by holding the option key when restarting the computer.
If you no longer have the Lion Installer you can re-download it from the App Store. Open the App Store, browse to Lion, and click Installed button while holding the option key. This will allow you to re-download the installer as mentioned here.
If your computer is already running Lion and you want to do a fresh reinstall you do NOT need a bootable DVD or USB key. Simply hold down the option key on boot and you will be able to choose Lion Image as a boot option.