For a successful upgrade or installation of Mac OS X, the installer will need to complete all of the following steps: Start up from the Install or Restore disc (all Mac OS X versions) Computer check (Mac OS X 10.4 or later) Source disc check (checks your installation DVD or CD, Mac OS X 10.4 or later) Destination (hard drive) check (checks the installation volume, Mac OS X 10.4 or later) Install Mac OS X (all Mac OS X versions) If you have issues with the above steps, or have any of the following questions, use the troubleshooting tips in this document. Unable to start up from the installation disc? Cannot complete computer check? Cannot complete source disc check (checking your installation DVD or CD)? Unable complete destination (hard drive) check (checking Installation Volume)? Install starts but does not complete (an alert message appears)? Issues after the installation finished? Is it OK for reinstallation to be slower?