Mac Boot Options

Apple systems have always used different key combinations to perform different tasks, just like all computer makers. However, finding those key combinations has always been an arduous task – they don’t come right out and tell you in the manual how to do some of these.

This list is a culmination of scouring the net and the list of sites visited is huge, the most simple way to find these combinations is using a Google search, click HERE to perform the same search I did to get started. I visited about 30 web pages and gleaned information from many to assemble this list. :>)

Boot key combinations:

Everybody knows about some of these boot key combinations, but some of the more obscure combinations have been long forgotten (like how many of us have a Quadra AV and use a TV as a monitor!) – Check these out, you may need one of them someday!

• C : Forces most Macs to boot from the CD-Rom drive instead of the internal hard drive. Only works with Apple ROM drives and with bootable CD discs.
• D : Forces the first internal hard drive to be the startup disk.
• N : Netboot (New World ROM machines only) – Looks for BOOTP or TFTP Server on the network to boot from.
• R : Forces PowerBooks to reset their screen to default size (helpful if you’ve been hooked up to an external montior or projector!)
• T : Target Disk Mode (FireWire) – Puts machines with built-in FireWire into target Disk mode so a system attached with a FireWire cable will have that device show up as a hard drive on their system. Very useful for PowerBooks!
• Mouse Button Held Down : Ejects any mounted removable media.
• Shift : Disables all extensions (Mac OS 7-9), or disables Login items when using Mac OS X 10.1.3 or later. Also works when booting Classic mode up just like you were using the OS natively.
• Option : When using an Open Firmware “New World ROM” capable system, the System Picker will appear and query all mounted devices for bootable systems, returning a list of drives & what OS they have on them. On “Old World” systems the machine will simply boot into it’s default OS without any Finder windows open.
• Space bar : Brings up Apple’s Extension Manager (or Casady & Greene’s Conflict Catcher, if installed) up at startup to allow you to modify your extension set.
• Command-V : Boots Mac OS X into “Verbose Mode”, reporting every console message generated during startup. Really shows what’s going on behind the scenes with your machine on startup!
• Command-S : Boots Mac OS X into “Single User Mode” – helpful to fix problems with Mac OS X, if necessary.
• Command-R : Boots into Mac OSX Utilities, including Disk Utility
  
• Command-Option : Rebuilds the Desktop (Mac OS 7-9).
• Command-Option-P-R : Erases PRAM if held down immediately after startup tone. Your machine will chime when it’s erased the PRAM, most people will hold this combination for a total of 3 chimes to really flush the PRAM out.
• Command-Option-N-V : Erases NVRAM (Non-Volatile RAM). Used with later Power Macintosh systems mostly.
• Command-Option-O-F : Boots the machine into Open Firmware (New World ROM systems only).
• Command-Option-Shift-Delete : Forces your Mac to startup from its internal CD-ROM drive or an external hard drive. Very helpful if you have a 3rd party CD-ROM drive that is not an Apple ROM device.
• Command-Option-Shift-Delete-#(where #= a SCSI DEVICE ID) : Boot from a specific SCSI device, if you have your 3rd party CD-ROM drive set to SCSI ID 3, you would press “3” as the # in the combination.