: This is the only major exception. If you are installing the Server edition (10.6 Server), you will be prompted for a serial number during the initial setup. These keys usually start with XSVR .
: Follow the prompts. When it finishes, it will reboot into your new desktop—no activation screens or online registration "musts".
The short answer is , you do not need a serial number to install the standard retail version of Mac OS X Snow Leopard. Apple historically relied on an "honor system" for its consumer operating systems. When you run the installer from a retail DVD or a bootable USB, it will simply ask you where you want to install the OS—no 25-digit alphanumeric codes required. The Exceptions to the Rule Do I Need A Serial Number To Install Snow Leopard
Do you have the , or are you trying to create a bootable USB from a downloaded image?
The Ghost in the Machine: Do You Need a Serial Number for Snow Leopard? : This is the only major exception
Do I need a serial number to reinstall Mac OS X? - Ask Different
: Insert your disc, restart your Mac, and hold the C key (or Option key) until the boot menu appears. : Follow the prompts
: Occasionally, if you call Apple Support to order replacement recovery discs, they will ask for your Mac's hardware serial number (found on the bottom of the machine or under "About This Mac") to ensure they send the correct version for your specific model. Why People Get Confused The confusion often stems from two places: