The Mac App Store Update for OS X Snow Leopard ensures future compatibility of the Mac App Store with OS X Snow Leopard. It is recommended for all Snow Leopard users.
● Installs a renewed intermediate signing certificate required by the Mac App Store. The certificate ensures that you can continue to use the Mac App Store in Snow Leopard to purchase new apps and run any previously purchased apps that use receipt validation.
● Includes improvements to Mac App Store alerts.
You can get the Mac App Store update for OS X Snow Leopard by running the Software Update mechanism from the Apple Menu. You must be running OS X 10.6.8.