OS X Lion has a special recovery mode which includes the option to reinstall the OS over the Internet, an internal AppleCare document reveals. The mode is invoked by holding down Command-R during boot, and presents users with several options. On a basic level it lets people access online help, or run Disk Utility to scan, repair, partition or even erase volumes. Under dire circumstances a person can restore from a Time Machine backup, or "reinstall Lion over the Internet from Appleís servers," according to the AppleCare note.
