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You are here: MacNN Forums > Hardware - Troubleshooting and Discussion > Mac Desktops > no EFI way to make my iMac stay on?

no EFI way to make my iMac stay on?
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Jun 28, 2012, 02:08 AM
 
Why Why Why does my iMac and my MacBook Pro shut off as soon as it starts up and shows the apple logo?
     
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Jun 28, 2012, 05:19 AM
 
Well it probably doesn't have much to do with EFI.

What if you boot one from a DVD?
I have plenty of more important things to do, if only I could bring myself to do them....
     
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Jun 28, 2012, 11:04 AM
 
won't boot from DVD. Push option, select the Hard Drive or DVD, it takes the choice, starts loading, and after the apple logo comes up, it shuts down. Can't get anything different by pushing the shift key and trying to load into 'Safe Boot'.
I did notice I can load into EFI, which led to my question. I can do fsck, but that doesn't seem to help. In fact, as soon as I type exit, it shuts down. I don't know if this is entirely normal, but I also noticed before I came to the point where it will let you run fsck that the verbose login mentions that the root device is read only.
     
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Jun 28, 2012, 03:59 PM
 
sounds fairly serious. Not hanging so probably not hard drive. Sounds like the logic board has failed.
     
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Jun 28, 2012, 05:56 PM
 
Possible, except that this condition exists on two machines and started after I had Target moved them together so I could transfer contents off the MBP and re-install OS X 10.6 on it. Contents wouldn't transfer, and then neither device would start up past the greyed-out apple screen. Before I lost access to the startup disk the disk utility on the iMac told me it was updating the boot partition. I'm wondering if that might be a part of the problem.
     
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Jun 28, 2012, 07:07 PM
 
What DVD are they failing to boot from? Sure its compatible? Can you pull the HDD from one and try the DVD?
I have plenty of more important things to do, if only I could bring myself to do them....
     
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Jun 28, 2012, 08:22 PM
 
So you rebooted on of the machines in Target mode, connected them with a Firewire cable, then what did you do?
     
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Jun 28, 2012, 10:35 PM
 
Then I attempted to copy my important files to a connected backup drive (connected to the computer, not the laptop), but the dialog box hung once it determined how many files it was going to copy. I downloaded CarbonCopyCloner and copied the files with that, but I didn't realize Cloner thought my backup drive was a single folder. It left everything in multiple places. I cleaned up, the laptop wouldn't repeat the process, and a direct copy still left the dialog box hanging, so I rested. But just before I did, I noticed my laptop's ID name was at the top of my finder window's ID bars. My Computer's name was missing. I restarted. The Apple logo came up. The computer shut down.
That is as I remember it, but I had been looking month's earlier into purchasing a Vid-card for my older MacPro 1,1 and heard of problems being had with computers crashing because the EFI didn't like the devices that had been installed on it's machine. I know about re-installing, which I did. I have run the install DVD on my computer (not the laptop), and the laptop is the one that won't run any DVDs bar none: no DiskWarrior, No Mentalist, No Limitless, no Mac OS X Install Disk 10.6, no nothing. The computer will run almost any DVD or CD. Neither of them however, will run their internal Hard Drives, which makes it a little bit of an odd problem. Did Target Disk Mode kill them? If not, what?
Well, I guess it's off to the Apple Store. I just hate spending so much money on something that I might have been able to cure by perhaps, using the Terminal, or something like that.
     
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Jun 28, 2012, 10:40 PM
 
Some one had suggested that the Extensible Firmware Interface might have been corrupted, and that running the terminal with the line 'frisk -u /dev/disk0' might update the boot record so that the hard drive would be 'blessed' or bootable again. Unfortunately, not so.
     
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Jun 28, 2012, 10:42 PM
 
Sorry, my bad. 'fdisk', not frisk... auto-correct caught up to me when I wasn't looking!
     
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Jun 29, 2012, 12:39 AM
 
Try resetting the PMU/SMC:

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

Make sure you read the directions carefully, they're slightly different depending on which Mac you have.
"…I contend that we are both atheists. I just believe in one fewer god than
you do. When you understand why you dismiss all the other possible gods,
you will understand why I dismiss yours." - Stephen F. Roberts
     
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Jun 29, 2012, 06:11 PM
 
Can you start the desktop booting from DVD by holding the C key, NOT the Option key?
     
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Jun 29, 2012, 08:36 PM
 
First of all, Apple won't usually charge you to fix software problems. Second, this sounds to me like one of them had a problem on its disk and you somehow copied it to the other one.

Have you tried target moving the laptop and running Diskwarrior or Disk Utility from the desktop? Have you tried reinstalling the desktop?
Also with the laptop in target mode, put a bootable DVD in the laptop and see if you can boot the desktop from that, just to check the DVD drive out. You can also try the other way around.
I have plenty of more important things to do, if only I could bring myself to do them....
     
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Jul 22, 2012, 01:49 PM
 
Have you zapped the PRAM? (opt-cmd-o-f at boot and chime three times)

If not, likely software corrupted. A reinstall of the operating system. It's likely not hardware because you can get into the multi-boot screen and it's not shutting off there.
     
   
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