Without a doubt, the upgrade version of Snow Leopard will be the most popular version available. And why not? At $29, it’s a steal. Even more amazing, Apple didn’t configure the installer to do any checking for qualifying installed versions of Leopard, so the upgrade version works just like a full install version, with one little exception.
Previous versions of OS X had installers that could perform various types of installations. The most popular types of installations were ‘Erase and Install’ (sometimes called a clean install), ‘Archive,’ and ‘Upgrade.’ The Snow Leopard installer has no option for performing any type of installation other than an upgrade, but with a few extra steps, you can get it to perform an ‘Erase and Install’ for you.
Erase and Install
The secret to performing an Erase and Install is to manually erase your hard drive using Disk Utility before you install Snow Leopard. To do this, you will need to perform the following steps.
- Boot from the Snow Leopard Install DVD.
- Erase the hard drive.
- Install Snow Leopard on the erased hard drive.
Step-by-step guides for performing Steps 2 and 3 are already available here at About: Macs, so I will walk you through Step 1, and then link to Steps 2 and 3. Once you perform all three steps, you will have a clean install of Snow Leopard on your Mac.
Boot from the Snow Leopard Install DVD
- Insert the Snow Leopard Install DVD into your Mac’s optical drive.
- Once the Snow Leopard DVD mounts on the desktop, the Mac OS X Install DVD window should open. If it doesn’t, double-click the DVD icon on the desktop.
- In the Mac OS X Install DVD window, double-click the ‘Install Mac OS X’ icon.
- The Install Mac OS X window will open and present you with two options. You can continue with a standard upgrade installation, or use the utilities included on the install DVD. Click the ‘Utilities’ button.
- The Snow Leopard installer will inform you that in order to use the supplied utilities, you will need to restart your Mac and boot from the DVD. Click the ‘Restart’ button.
Using Disk Utility from the Snow Leopard Installer
- After you reboot your Mac, the Snow Leopard installer will ask which language you want to use as the main language. Make your selection and click the right arrow key.
- The Install Mac OS X screen will display. Click the ‘Utilities’ button.
- In the Apple menu bar, select ‘Disk Utilities’ from the Utilities menu.
- Disk Utilities will launch. Select one of the following instructions, depending on what you wish to do.
- Erase a Volume. Use these instructions to erase an entire volume. Be sure to back up all of your data first.
- Format a Hard Drive. Use these instructions if you wish to erase an entire hard drive, including any volumes/partitions it may contain, and not create any new volumes/partitions. Be sure to back up all of your data first.
- Partition a Hard Drive. Use these instructions if you wish to erase and partition a hard drive. Be sure to back up all of your data first.
Complete the Snow Leopard Installation
To complete the installation, follow the instructions in ‘Snow Leopard Install: Basic Upgrade Install of Snow Leopard.’
That’s all there is to it. You now have a clean installation of Snow Leopard that mimics the ‘Erase and Install’ option available in previous versions of OS X.