The keyboard on your Intel based Mac is a powerful tool even before Mac OS X Lion launches. You can use it to do a variety of things like selecting the media or startup drive to boot your Mac with, launching diagnostics, or performing resets that might help resolve problems with your Mac.
Select An Alternative Startup Disk
If you press and hold C after turning your Mac on it will start from a bootable CD or DVD, such as the Mac OS X Install DVD or USB stick that came with the computer.
If you have multiple startup disks attached to your Mac or perhaps a disk partitioned with multiple bootable partitions simply press and hold the Option key while starting your Mac. You’ll be presented with the Mac OS X volumes you can start from. Just select the one you want with the arrow keys and press Enter to startup your Mac from that drive or volume. Bonus: if you press and hold the N key you’ll also see the first available Network volume in the list.
Start Your Mac Using Netboot
As an alternative to the startup key sequences above you can simple press and hold N as your Mac starts to startup from a compatible network server on your local network using Netboot.
Perform a Mac Hardware Test
If you need to do a hardware test you can press and hold D after starting your Mac to launch the Apple Hardware Test.
If you are instructed to do a NVRAM or PRAM reset press and hold Option-Command-P-R until you hear your Mac make the start-up chime twice.
Force Eject Optical or Removable Media
Now here’s a good one when you have optical media in your optical drive or if you have problems ejecting the media. Restart your Mac and press and hold Eject, F12, or hold the mouse or trackpad button. Any of these actions will cause your Mac to eject any removable media that might be inserted. Especially a CD or DVD.
Start Your Mac in Target Disk Mode
Pressing and loading the T key during startup forces your Mac into Target Disk Mode. Target Disk Mode turns your computer into an external disk drive or at least it acts like one. You’ll have full access to the startup disk on that computer via FireWire or Thunderbolt unless you’ve secured your drive like I showed you how to do earlier.
Start Your Mac in Safe Mode
Here’s a handy key sequence to know if you need to troubleshoot Mac OS X problems or problems with apps on your Mac. If you press and hold the Shift key during startup your Mac starts in Safe Mode and that will temporarily disable all login items associated with your Mac and your user account.
Verbose Startup Mode
If you are an experienced Mac OS X or Unix user you’ll find Command+V for Verbose startup mode to be handy for troubleshooting startup issues. While in this mode you’ll see things you wouldn’t normally see while your Mac starts.
Single User Startup Mode
Experienced Mac OS X or Unix users will find the ability to start their Mac in Single-User mode using Command+S to be handy for advanced startup sequence troubleshooting. You’ll need to know a bit about Unix commands to make Single-User mode really useful.
Start Lion HD Recovery
Finally, if you are using Mac OS X Lion you can press Command+R during startup to start the Lion Recovery utilities.
Do you know any other useful startup key sequences? How about sharing yours by leaving a comment.