Startup Keys – Boot Options

6/14/2003 in Misc Notes by Chris Janton | 22 comments

Snagged this from Other World Computing at this page…don’t want to lose it out there.

http://eshop.macsales.com/reviews/Framework.cfm?page=/Tips/Key_Combinations/bootkeycombos.html

Obscure Startup Key / General Use Key Combinations

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-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.

And, the obscure ones :>) Older computers only, on some.

  • Command-Option-I : Forces the Mac to read the disc as an ISO-9000 formatted disk
  • Command : Boots with Virtual Memory turned off.
  • Command-Option-T-V : Forces Quadra AV machines to use TV as a monitor.
  • Command-Option-X-O : Forces the Mac Classic to boot from ROM.
  • Command-Option-A-V : Forces an AV monitor to be recognized correctly.

If you see a command here that is incorrect, or know of one that should be added, please drop me an email and I’ll add it. I plan on adding other different types of key command combinations here as future "quick tips". Thanks!

22 comments

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  1. David on 7/14/2005 at 11:26 am

    Thank you! I have an OSX/OS9 G3 and hadn’t booted it in OS9 for quite awhile. When I went to do it, it hung because I had installed a new CD-R. Thanx to you I found how to bypass extenstions and get the darn thing started.

    Much appreciated!

  2. John Johnston on 11/6/2006 at 3:15 am

    Command-Option-O-F
    I have a problem with my internal speakers not working on my new Macbook Intel 13″ running tiger 10.4.9. I was advised by an apple form user to do the above which is also in your list of boot options but nothing happens – it just boot normally. Do you have any comment? thanks, JJ

  3. Richard on 1/8/2007 at 7:02 pm

    The Command-Option-O-F sequence (and all others relating to Open Firmware) only work on PowerPC Macintoshes from the late ’90s to the G5 range. Intel Macs do not use Open Firmware and as such Cmd-Opt-O-F, the sequence to boot into the Open Firmware command prompt, does nothing.

  5. Andrew on 3/9/2007 at 3:13 am

    If I have a version of Linux on an external drive will ‘option’ key find this an option to boot from?

  7. fred kirby on 8/21/2007 at 2:09 am

    would I have to do this everytime?
    or can I set up a list of priorities?

  9. oscar on 5/5/2009 at 1:06 pm

    have a machine that seems to be stuck in single user mode. The splash screen (login screen) comes up and then disappears all boots straight to command prompt login:

    any one out there know what might cause this and how to fix?

  10. big tom on 5/8/2009 at 9:14 am

    The one that gets me out of trouble the most: unplug the machine, turn it on (nothing happens, duh, but you’re releasing pent up capacitors (or whatever)), then plug it back in and turn it on. Voila!

  11. carl on 7/28/2009 at 3:47 pm

    can the command prompt be ran on an external screen. .my macbook has a crack in it

  12. david v. on 8/23/2009 at 8:18 pm

    i have a powerbook g4 laptop model a1010. i continue on getting a blank screen and after a few secs i get the broken mac folder that switches back and forth with a ?. i have tried various key commands to boot..no luck. :(

  13. Tonny on 9/21/2009 at 8:50 am

    i have a mac pro 2.4Ghz. everytime i boot the mac, i have to pull out the network cable, otherwise it shows up a flash earth icon in the middle of the screen. how to overcome that problem? thanks much!

  14. Kasm279 on 10/28/2009 at 4:44 pm

    For all you asking for support, you probably wont get any here. You would be better off hopping on the Freenode IRC server and joining ##mac. (This is not meant to be an advertisement, only a little bit of help…)

  15. David on 12/20/2009 at 9:42 am

    All intructions are always incomplete and therefore useless.

    1. There are no option or command keys on the Apple Keyboard so which keys is he referring to?

    2. When do you push these keys down – before pressing the power key, during, or after?

    “No one knows their own business anymore. Life has become too complicated for managers to manage.”

  16. Mark on 12/28/2009 at 5:10 pm

    Really David? Is it really easier to whine on here about your own ignorance than to simply go to google or apple.com and educate yourself? Also, no where is the word “instructions” used in the blog post. This is clearly a reference, and a useful one to those that understand the context.

  17. Eddie on 2/5/2010 at 8:36 am

    I have a macbook G4 with a newly installed hard drive. I can’t get it to boot from the original install disk. This is a great computer, and I’m not giving up on it. Any help would be greatly appreciated. I’ve tried every key combination to get it to boot. Even cleared out the PRAM. HELP!

  18. bretuoba on 2/10/2010 at 12:27 pm

    I get white screen when I try booting snow leopard

  19. Mike on 3/30/2010 at 9:56 pm

    I have windows installed with bootcamp on my imac. I normally hold down the option key to boot with windows, and when I do that, the selection screen comes up where i press the arrow keys to choose which partition to boot from. Thats all fine and good, but recently, the selection screen has been coming up every time i boot, and when i select the mac icon, it shows the apple logo and then freezes. the only way to boot normally is to hold down any key while its booting. is there any preference I can change so that it goes back to normal? thanks.

  20. PC person forced to work on MAC on 4/30/2010 at 3:03 am

    Any ideas how to translate this in English: “Also works when booting Classic mode up just like you were using the OS natively” ???

    No, ok, ok, it is a good guide… I guess. I’m just trying to boot Classic from an OSX machine and it’s not workin’

  21. awr on 6/10/2010 at 9:45 pm

    at some point classic has been abandoned; re: previous post. very likely it’s a no-go; you would need to have an older version of os-x on a different partition or drive.

    -awr

  22. michael on 7/17/2010 at 1:21 am

    i have a problem here somebody help me.my system is not booting if i turn it on all i see after sound is a small box with question mark(?) inside that box so i want to install a new mac os but all lost my original cds