I had an issue with the MAC OS and couldn't repair the MAC os i have (10.4) on my intel duo core macbook.

So i install Ubuntu 11 on my mac and works perfectly. I am selling my laptop now to get the new macbook pro but the person who wants it needs mac os but every time I try to install it shows a folder with a question mark when I put the mac cd (Original CDs 10.4 that came with the laptop)

so i booted with the "option" and shows my hard drive, put the mac CD and it ejects it, put the ubuntu CD and works perfectly.

I try to clear the nvram: Command + Option + O + F


what can i do to install mac os?

  • Is this the install CD that came with the computer, or a different one (and if different, what exactly is the CD)? Commented Jun 5, 2013 at 15:16
  • @GordonDavisson edited my question Commented Jun 5, 2013 at 15:22
  • 1
    Is the CD readable when you insert it while in Ubuntu and does it show content and files then? Maybe the CD is scratched, dirty or broken?
    – Nicholaz
    Commented Jun 5, 2013 at 17:23
  • @Nicholaz Yes the CD is readable, I am able to read it from my other Ubuntu machine using HFS mount, I can see all its content and read files. Also can boot from another MAC I have no problem. Commented Jun 5, 2013 at 18:01
  • Weird. Can you make a clone of the CD (preferably on another computer) and see if the clone boots?
    – Nicholaz
    Commented Jun 5, 2013 at 18:33

3 Answers 3



Command-Option-O-F alone, immediately after the startup sound:

  • presents an Open Firmware prompt, only on Macs that use Open Firmware
  • does not reset NVRAM.

At an Open Firmware prompt you might enter a command such as reset-nvram – but it's not the usual approach.


Use Command-Option-P-R as instructed in Apple's article: About NVRAM and PRAM.

Additional advice

If the optical disc is loaded whilst the Mac is powered off, then C – pressed immediately after the startup sound, and held – should allow the Mac to boot from a compatible disc.

If the C key approach does not work – and if you have reset NVRAM/PRAM – then consider the possibility of a marginal optical drive and/or marginal disc.

Don't rush to reset the SMC.


Apple's Transition from Open Firmware to Extensible Firmware Interface – MacTech | The journal of Apple technology. (2007)

What is firmware? – not a great article from Apple; it mentions Open Firmware but not EFI under a list of modern products that probably do not use use Open Firmware.

"To continue booting, type 'mac-boot' and press return" Message

Intel-based Macs: Resetting the System Management Controller (SMC)

  • I tried to press C and it works for a Ubuntu DVD/CD but not for the Mac DVD. The MAC DVD works for my other macbook pro. So I don't think the CD is broken nor the drive since I can read the Ubuntu DVD Commented Jun 10, 2013 at 13:57

try to take the dvd out of the question. there might be something wrong either with the disk or the dvd-drive that doesnt allow you to install

make a bootable usb stick as per the following instructions from a friends mac with a more current osx http://www.maciverse.com/install-boot-os-x-leopard-from-a-usb-flash-drive.html

and then try the "option" press while booting to choose where to boot from...

Here is also a guide on how to do this (install the osx from a USB) for osx 10.4 btw

install boot osx 10.4 from usb drive


Try clearing the SMC? https://discussions.apple.com/thread/4550751?start=0&tstart=0 I don't know if your mac is new enough to have an option for resetting the SMC but you might give it a try, this is one of the well-known issues associated with having a messed up SMC.

Unless your Mac is PPC and quite old, the command-option-O-F summons an open firmware prompt (which most people use to reset thing) and not a NVRAM/PRAM reset. For that you need command-option-P-R which sets a few variables to their default values.

  • I would disagree with the characterization that a SMC that needs reset would cause one OS to boot but another OS to not boot. It could be an edge case, but I'd focus more on the OS that isn't booting than the system (which works with the alternate OS) or the alternate OS (which works with the system).
    – bmike
    Commented Jun 9, 2013 at 15:18

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