Misc Notes

Startup Keys – Boot Options

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

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!

56 replies on “Startup Keys – Boot Options”

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!

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

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.

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

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?

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!

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

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 luck. πŸ™

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!

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…)

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.”

Really David? Is it really easier to whine on here about your own ignorance than to simply go to google or 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.

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!

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.

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’

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.


i have a problem here somebody help 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

I have a G5 with two sparate OSX operating systems defined (each on its own hard drive) both running Leopard. Until a few months ago, I could restart the system and depress the option key and I would get a screen showing my bootable HDs and I could choose which OS I wanted (with different applications on each). Since then (and it might have been an update that changed things, I’m not sure) when I depress the option key while rebooting… It WILL NOT REBOOT WHATSOEVER! I have to power it down and boot from the last bootable drive selected. How do I get that option back?
Any help would be apreciated

running a g5 trying to reinstall leopard on the computer (which i have done before) but now its saying that it can not validate the ‘Essentials’ package. WTF?? Anyone got anything??

Please can you tell me command on keys for (windows) keyboard when it boot up at very start cause i don’t have Mac keyboard… also my Mac is G4 with 10.4 OS X also can you help me to find out how to make ZIP Disk become boot up. Thanks!

I’m not going to address individuals, but a few of you have had the same problem.

For the guy that keeps booting and getting the blue “globe”, try holding down D after the chime (when you start up) That will force the computer to start up to the first available hard drive. It sounds like the computer is trying to boot from the network. If holding down D works, the first thing you should do is go to Preferences -> Startup Disk and select the correct disk. That way next time you start up, it will use that disk automatically.

Doing that also might solve the problem with always booting up into Startup Disk selection. When you get to the screen to select either Mac or Windows, boot into the Mac OS, go to Prefs -> Startup Disk and pick the Mac. This should make the computer use Mac OS by default, with no special keys needing to be held. If you want to start into Windows, then holding down Option should still do the trick.

Whenever I have startup disk problems like that, I can usually fix the problem with either holding “D” to boot to main drive, or “Command-Option-Shift-Delete-#” to boot to a specific drive/partition.

If all that fails, pop in your Mac OS install CD/DVD, hold “C” to boot from, run Disk Utility to repair the drive and/or permissions. When finished, quit Disk Utility, go back up to the menu and find “Startup Disk” to select the proper OS like explained in the other methods. Restart the computer without holding any keys, and see what happens.

These options aren’t in any particular order, I just assume not use my install DVD unless I have to. Some people might find it’s best just to boot from the DVD and go down that road first, since you can’t use Disk Utility ‘repair disk’ feature on a disk that you are booted from, and both options allow access to the Startup Disk preference.

Hope that helps someone! Every situation is different, and I didn’t exactly have a ton of detail to work with, so you might find none of these suggestions work.

When I turn on computer I get a blue screen only. I have tried holding D and C keys and finally something popped up asking which language. I chose english and it said preparing installation. But it is frozen now. I am at wits end. Any suggestions? Thanks in advance.

When I turn my MacBook on it goes to the desktop without the dock and I can’t click anything (nothing opens) all that works is the mouse. I can’t open finder or preferences or anything and the only way it turns off is to hold the power button. What can I do at startup to go back to the last working settings?

I NEED help… I have a Macbook (Black) runs 10.5 I believe. I think my software is messing up.. I am getting the question mark flashing on start up. I bought a new hard drive , but I my internal cd is not working. I have a external with new software.. How do I get to the boot options to boot from my external hard drive? is the open apple button the command button ?

Converted PC user…


I have MacBook Pro 2010 model, with Intel Core 2 Duo with MAC OS 10.6.4 installed on it. I try some of the shortcuts mentioned here at startup, but nothing happens as if I did not use any shortcuts. For example, I am pressing “C” button while I try to boot system from Mac OS X 10.6.3 Install DVD, but it just boots to normal desktop. Other example, I press “D” to run diagnostic utility from Applications DVD, and again nothing happens other booting to normal desktop. Do you have any solution to this problem ? If one day my hard disk will crash, I can’t boot from OS X DVD to install OS X to new unformated disk. Any help would be appreciated.


You saved my day !! holding down the mouse button to eject media ( that was classic !). who would have thought about that? I was stuck while installing win 7 , and had to go back to OS X. Saved !!

Hi need help plz

Iam using mac tiger 10.4.11 and everytime i switch on the mac the black and white screen appear with this; /etc/master.passwd: no such file or directory

How to fix it?

hi all,
I have a SATA drive out of a G5 iMac. The computer just stopped working so I put the drive in and external drive case. The drive worked on my Intel Core 2 Duo iMac as an external drive, I thought great I’ll copy stuff off later cos I’m busy, I safely ejected it. Now it doesn’t work.
I tried the Command-Option-Shift-Delete boot up this didn’t work either.
Help me please

Hi! My PowerBook G4 is stuck with a big half eaten apple in the middle of the screen after the chime. I tried every key combos, but nothing helped. Before that the machine was working. I shut it down, and next time I turned it on, I got the apple logo after the chime, and nothing else. The background is white btw. if it helps. Thank you in advance!

Missed one!
Boots Snow Leopard in the “extra dry cappuccino” mode. But have your mug ready because it comes out fast.

-Espresso grind goes in the optical drive.

I have an old PowerPC G3, blueberry that the internal cd rom is fried and I’m trying to install Panther from an external drive. Nothing is working. I’m thinking I’m going to have to install Panther onto an external Hard Drive, including to copy the Startup Disks (not sure if it will work) and then make that the boot drive, then try to install it from there? What a pain in the butt! Any ideas would be appreciated if there are anymore old school Mac people out there.

A lot of these problems (especially the flashing ?) can be solved by decreasing the ram. eg: if there are two 512MB sticks, pull one out and then boot, quickly hold down option, command, P and R keys until you hear three chimes. If that doesn’t work; try resetting the firmware: boot and quickly hold down the option, command, O and F keys, then type: reset-nvram (non-volitile ram) and hit enter, type reset-all and re-boot (you may need the fw pwd). If problems persists, try zapping the pram again. If you succeed, you can install more memory (maybe not the same as the former could have been bad, just make sure they are the same).

***** Important to note, this does not apply to all the flavors of devices above, but should work on the G4’s. Last resort, reset the PMU (G4’s) by holding down the shift key, ctrl, option and power for no more than ten seconds.

***** Again, this doesn’t apply to the Intels; that is a different ball game.

Hi, I have just bought a new hard drive for my macbook. I do not seem to hsve install discs for os x 10.5. I have a backup through time machine which I was hoping to boot through a usb external hard drive. I tried command-option-shift-delete but it does not do anything. Is there another command to boot from external hard drive (usb)? or any other ways. preferably i do not want to get a case for the internal hard drive and the only other way i can seem to find is through migration using another macbook. any ideas??

i have a 2008 intel based imac….the hard drive is completely screwed…i have an external hard drive i use in place that connects via usb, however i am having trouble determining why it is that everytime i unplug it i have to go thru hell to get it to not give me a white screen. It makes all noises and tones like it should, just no picture. If i try to boot from the disc drive 90% of the time it will spit it right back out…I have to mess with it sometimes for weeks trying different things before it will come back to life and ask me where i would like it to store the os. This is gettin so old…please if anyone has any suggestions or ideas as to why this is or how to fix it, it’d be much appreciated.

Can anyone help me?

I have a Macbook pro OSX.

I loaned it to a friend and locked the HD now I can start up the computer. It just shows the grey screen and kernels…I tried put in a couple of repair disc and they won’t come up…

Any advise would be most appreciated.


thanks for all the startup commands…incredibly helpful !
my problem is that i cant just get into bootup mode with C from either diskwarrior or mac g5 install disks (Power PC g5 Power Mas 7.3 …2007)
tried checking that my hard drive was the start up drive and seems ok.
cd drive works fine with regular cds
have done pram 3 times and nrvm as well…
OnyX is giving me all clear and so is permissions in Mac OS as far as my main drive goes
and Danny I can get startup absolutely every problem… its just bootup with all the bootup disks that will simply not happen for me
any ideas ? and thanks again for the wonderful collection of trophy commands

problem solved !
i was using defective mac install cds and a Disk Warrior that was out of date… found correct Disk Warrior cd just now and I was able to get in to BOOT-Up mode first time !
Thanks again for all the priceless tips

I’m kind of a cave-man regarding computers so I’ll just describe what I see: When I turn on my mac it makes the mac sound, then the screen comes on black and white screen with the little wheel spinning, then screen changes and it goes to the blue bar that fills in and it seems to completely fill but nothing else happens.

Hi guys I have an old lime green slot loading iMac that was given to me as it was going to be thrown out. Up until a week ago it worked fine, not it boots up shows that it’s loading osx with then just goes to a blank blue screen with no finder or anything. It’s running osx 10.2.8 I have no startup discs any advice is appreciated

my laptop is mac powerbook G4 that having the hdd complaint it will be change the another hdd but it not get the any bootable media i holding the “c” key but it not work
i having the iboot cd but still not working please help me

Hi! My iBook G4 won’t start up. The power supply is working (yellow and green lights), but nothing inside sounds like it’s working. Genius bar thinks it’s the service board. Since my computer is almost “antique,” I would have to send it away to get it fixed (“depot” flat-rate option). So, I’d like to recover my data from the harddrive before I send it away because it’s possible they may replace the harddrive, in which my files will be lost. I’ve retrieved the HDD out of my laptop and put it into an external enclosure.

Basically, I was wondering what the best external harddrive storage device is easiest and best for mac files? Are there devices that don’t need reformatting that are reasonably priced? Do I need to use another Mac to tranfer over the files, or will a PC work?

please help! thanks :0)

I find this very useful to begin with. But I am having serious problems. I don’t have the reboot CD key for my 2009 macbook laptop. I get the prohibited sign after starting up. If I use the d key, it says I have no hard drive problems. None of the other commands are working. help me please! Much appreciated

Hey Everabody πŸ™‚

I have one of the first NW mac’s commonly known as the Yikes PCI…
I have after many weeks finally got Leopard Successfully booting to a Stable Desktop…

This has been a real learning curve. I noticed that with mine the OF commands (preboot key combinations)
arent all there! I have some of the NW commands and some of the OW…
For example …

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 itΒ’s default OS without any Finder windows open.

DOES NOT WORK. I get no boot choice menu.

And because of my Yikes limitations I can not upgrade OF to the later version so im stuck @ Version 1.2f2

So I’ve accepted that but would like to learn some of the typewritten commands.
Especially any that I could use to choose which HDD I boot from would be great.

or is there some way to patch my OF to allow commands like OPTION. (SYSTEM PICKER)?

Well I answered my own Q?

So here is what I found incase someone else needs this…

once in OF


You can type devalias and get a list.

from that list I found these:

hd refers to the first hard drive.
ultra0 the first hard drive.
ultra1 the second hard drive.

If you have sata these may differ!

So I find that I can type:

boot ultra1:,:tbxi

and the system boots from the second hard drive.

change out the ultra1 for ultra0 or hd and well its self-explanatory…

Note: there are aliases for CD and other choices as well one might try.

Not sure what tbxi means or if you use that when choosing to boot from the CD.

I have not tried it yet.

i have a problem in mac os x. i have installed in intel based pc but when i start the pc and boot menu is not come. if i

inserted the dvd of mac and restart the system then it shows the boot menu. is there any problem in the mac or

something else. please help me to this problem.

i have a mac that i just bought off of someone online they didnt give me any paper work of the boot cd or whatever and after i hooked my internet up to it, it locked up on me what can i do i deleted the persons number and have no way of contacting them there add is no longer up any suggestions

[…] If you only have the old machine and do not want to pay for an expensive Apple keyboard/mouse set, just plug in a simple PC desktop set. I found myself an Apple look-alike-white set from Trust. (In the past I have been unlucky more than once with Trust products, but this one still works.) Of course, you will have to map the keys to the specific Apple functions. One of Microsoft’s more useful pages will help you out. Specific Apple startup keys or boot options can be found on this page. […]