Startup key combinations for Intel-based Macs

KeystrokeDescriptionPress C during startupStart up from a bootable CD or DVD, such as the Mac OS X Install disc that came with the computer.Press D during startupStart up in Apple Hardware Test (AHT).Press Option-Command-P-R until you hear two beeps.Reset NVRAMPress Option during startupStarts into Startup Manager, where you can select a Mac OS X volume to start from. Note: Press N to make the the first bootable Network volume appear as well.Press Eject, F12, or hold the mouse or trackpad buttonEjects any removable media, such as an optical disc.Press N during startupAttempt to start up from a compatible network server (NetBoot).Press T during startupStart up in Target Disk Mode.Press Shift during startupStart up in Safe Boot mode and temporarily disable login items.Press Command-V during startupStart up in Verbose mode.Press Command-S during startupStart up in Single-User mode.Press Option-N during startupStart from a NetBoot server using the default boot image.