How to Perform a Clean Install of Snow Leopard OS X 10.6

OS X Snow Leopard Installation screenshot
Screen shot courtesy of Coyote Moon, Inc.

Without a doubt, the upgrade version of Snow Leopard will be the most popular version available. And why not? At $19.99, it’s a steal (available from the Apple store). ​Apple continues to sell OS X Snow Leopard even though it was first released in the summer of 2009.

Available only as a DVD directly from Apple, its persistent availability is because it is the minimum requirement for accessing the Mac App store and thus the only way for anyone with an older Mac to upgrade to any of the newer Mac operating systems.

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.

  1. Boot from the Snow Leopard Install DVD.
  2. Erase the hard drive.
  3. Install Snow Leopard on the erased hard drive.

Step-by-step guides for performing Steps 2 and 3 are already available here at Livewire, so let's walk through Step 1. 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

  1. Insert the Snow Leopard Install DVD into your Mac’s optical drive.
  2. 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.
  3. In the Mac OS X Install DVD window, double-click the Install Mac OS X icon.
  4. 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.
  5. 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

  1. 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.
  2. The Install Mac OS X screen will display. Click the Utilities button.
  3. In the Apple menu bar, select Disk Utilities from the Utilities menu.
  4. Disk Utilities will launch. Select one of the following instructions, depending on what you wish to do. Be sure to back up all of your data first.
    1. Erase a volume
    2. Format a hard drive
    3. Partition a hard drive

When you have finished using Disk Utility, select Quit from the Disk Utility menu. You will be returned to the Snow Leopard Installer to continue the installation.

Complete the Snow Leopard Installation

To complete the installation, follow the Snow Leopard basic install instructions.

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.

Accessing the Mac App Store

At this point, you may be asking yourself where is the Mac App store that was supposed to be included with OS X Snow Leopard? Actually, the Mac App store was not part of the original version of Snow Leopard but was added in OS X 10.6.6.

To gain access to the store, you may need to perform an update to your system software. You can do so by selecting Software Update from the Apple menu.