Option – Boot directly to the Startup Disk manager Command+R – Boot into Recovery Mode of OS X (modern versions of OS X only) C – Boot from a CD/DVD T – Boot in Target Disk mode (FireWire or ThunderBolt only) N – Boot from an attached network server (NetBoot mode) X – Attempt to force Mac OS X to boot Shift - Boot up in ‘Safe Mode’ which has limited functionality but disables third party extensions Command+V – Boot into Verbose mode Command+S – Boot in Single user mode