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

Use this method to get around the upgrade-only restriction

Apple ceased support for Snow Leopard OS X 10.6 in 2014 and has released 10 newer versions of OS X, and then macOS, since. This article has been archived here for posterity.

Snow Leopard OS X 10.6 was the earliest version that allowed access to the Mac App store and thus was the only way for anyone with an old Mac to upgrade to newer Mac operating systems. Apple didn’t configure the installer to check for qualifying installed versions of Leopard, though, so the upgrade version works just like a full-install version. There's one exception, however: The Snow Leopard installer has no option for performing any type of installation other than an upgrade. Nevertheless, a few extra steps make "Erase and Install" possible.

OS X Snow Leopard Installation
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This process involves three steps:

  • Boot from the Snow Leopard Install DVD.
  • Erase the hard drive.
  • Install Snow Leopard on the erased hard drive.

Here, we focus on the first two.

Booting From the Snow Leopard Install DVD

Here's how to 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, to use the supplied utilities, you must restart your Mac and boot from the DVD. Click Restart.

Erasing or Reformatting the Hard Drive

For this step, you'll use Disk Utility from the Snow Leopard installer. Here's how:

  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 Utlities > Disk Utilities.

  4. Disk Utilities will launch. Select one of the following options:

    Be sure to back up all of your data first.

  5. 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. You now have a clean installation of Snow Leopard using a method that mimics the Erase and Install option available in previous versions of OS X.

Accessing the Mac App Store

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 might need to update your system software. Select Software Update from the Apple menu.