# iMac stuck in bootup/shutdown cycle



## fpdiver (Feb 18, 2017)

I have an iMac (Model details: iMac, Late 2011 model, 27 inch, 4 Gb RAM, Intel 3.4GHz i7) which has recently started shutting down midway through its boot up process (when the Apple Logo is displayed). It continues in that cycle until I turn it off.

When run in Verbose mode, I get the following message:

pid exited (signal 0, exit 1)panic(cpu 2 caller 0xffffff80093cicde) Launchd died\nState at last exception:\n\[email protected]/SourceCache/xnu/xnu-2782.20.48/bsd/kern/kern_exit.c:363

Debugger called: <panic>

I have tried the following:

Cmd - R: (recovery mode) - the iMac doesn’t respond to this and remains in its boot up/shut down cycle
Shift: (safe mode) - behaves the same as for recovery mode.
I used the Option key to load boot menu - it won’t boot from recovery partition and won’t boot from a bootable installer for Sierra on a USB disk (shuts down again).
I used Alt+Option - won’t boot from Internet (tried both WiFi and Ethernet)
I have reset the NVRAM
I have run memtest86 and the memory checks out ok
I ran fsck -fy from single user mode and that checks out OK (but trying to boot after running it gives the same behaviour).
I have booted it in Target Disk mode attached to a Mac Book Pro and used Disk Utilities to scan the disk which checked out ok.
 
Can anyone suggest any other options I can try or help me diagnose the problem? Or is my only hope a genius bar?

I thought it would be possible to install a new OS on the disk via Target Disk mode but I that doesn’t seem to be the case. I’m not precious about any of the files on the disk (and could get them off anyway if needed using Target Disk mode) so if solutions involve formatting the hard drive then that is no problem.

Any help greatly appreciated!


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## MartyF81 (Jan 23, 2013)

Get your files off the disk now if you can.

What version of MacOS were you running on it? 

Can you try CMD + OPTION + R when booting to see if you can get into Internet Recovery Mode?

If you can get into that mode... you will be able to eventually open Disk Utility directly on the machine and attempt to format the drive... and reinstall the OS by downloading it directly from Apple.


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## fpdiver (Feb 18, 2017)

Thanks for your reply.

I tried CMD + OPTION + R before posting but omitted that from the list in the my post.

Unfortunately I can't remember the version of OS we had, probably Mavericks or Yosemite, certainly not Sierra.


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## MartyF81 (Jan 23, 2013)

If you cannot get into Internet Recovery mode.... it sounds like you might have some type of low level Logic Board hardware issue.

Internet Recovery mode is a very low level service... You should normally be able to boot into that even with a completely dead hard drive.

If you have an Apple store close to you, I would take it to them so they can take a look.


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## oJosh732o (Oct 22, 2014)

Try Command + Option + P + R when booting.


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## MartyF81 (Jan 23, 2013)

oJosh732o said:


> Try Command + Option + P + R when booting.


They have already done that.


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## oJosh732o (Oct 22, 2014)

MartyF81 said:


> oJosh732o said:
> 
> 
> > Try Command + Option + P + R when booting.
> ...


Sorry about that... I overlooked where he said he had already reset the NVRAM.


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