Key combinations to troubleshoot your Intel-based Mac at start-up
Many articles you read on Mac troubleshooting mention troubleshooting methods like resetting the NVRAM, starting in FireWire Target Disk Mode, starting in Safe Mode, or starting in Single-User Mode, but fail to explain exactly how to do that.
Many articles you read about Mac troubleshooting mention troubleshooting methods such as resetting the NVRAM, starting in FireWire Target Disk Mode, starting in Safe Mode, or starting in Single-User Mode, but fail to explain exactly how to do that. This article breaks it down for you.
Apple has released a knowledge base article describing the key commands and what they enable when pressed during start-up:
- Press C during start-up: Start from a bootable CD/DVD, such as the Mac OS X Install disc.
- Press D during start-up: Start the Apple Hardware Test when the Install DVD 1 is inserted in your Mac's drive.
- Press and hold (Command + Option + P + R) until you hear two beeps: Reset the NVRAM.
- Press Option during start-up: Loads Startup Manager, enabling users to select which volume they would like to boot from. Pressing N will show the first bootable Network volume as well.
- Press the Eject button, press F12, or click and hold the mouse or trackpad button: Ejects any removable media.
- Press N during start-up: Attempt to start from a compatible network server (NetBoot).
- Press T during start-up: When two Macs are connected via FireWire, this will start one in FireWire Target Disk Mode (two Macs with FireWire ports are required).
- Press Shift during start-up: Starts your Mac in Safe Mode, temporarily disabling log-in items.
- Press (Command + V) during start-up: Starts in Verbose Mode.
- Press (Command + S) during start-up: Starts in Single-User Mode.
- Press (Option + N) during start-up: Start from NetBoot server using the default boot image.