Are you planning to install Snow Leopard on or are you trying to set it up in a virtual machine like VMware or VirtualBox?
Finding a clean, uncompromised copy of Mac OS X 10.6 is challenging because Apple no longer sells the physical retail retail DVD or hosts it on the official Mac App Store. However, reputable community archives keep this operating system accessible for preservation purposes. 1. Trusted Community Archives
This only works on Macs that originally shipped with Snow Leopard or earlier. Apple’s servers still host this file. Mac Os X 10-6 Snow Leopard Download Dmg
You are attempting to install on unsupported hardware. Your Mac is either too new (2012+ MacBooks usually reject Snow Leopard) or the date on your system clock is wrong. Set your Mac's date to via Terminal ( date 082820092010 ) before running the installer.
Plug your bootable Snow Leopard USB drive into the target computer. Are you planning to install Snow Leopard on
This takes 15–20 minutes.
Mac OS X 10.6 Snow Leopard Download DMG: A Complete Guide to Legacy Installation You are attempting to install on unsupported hardware
: Hosts "Mac OS X 10.6 Snow Leopard Retail" images (DMG/ISO) uploaded by users for preservation.