Trying to figure out what's causing kernel panic

Discussion in 'macOS' started by muonium, Oct 28, 2013.

  1. muonium macrumors newbie

    Oct 27, 2013
    My mac is showing cycling kernel panic at boot time and I am trying to figure out what is causing this. Any help would be appreciated.

    When I try the safe boot (with shifty key), my mac boot with no problem.
    So I tried the verbose boot (command-v) and the terminal is showing something and then erase them. The mac is repeating this since it is in the cycling kernel panic mode. And there is no way to pause the terminal to see what is going on.

    So I tried singe-user boot (command-s) and this boot is very different from verbose boot. It does't go through the kernel panic loop and simply show the prompt of %root. So I typed "sudo dmesg | more" but it shows the system log of single-user boot not the verbose boot. So there is no way to get the system log of verbose boot.

    Is there a way to stop the verbose boot from kernel panic loop so that I can get the system log from "sudo dmesg | more"?
  2. ElectricSheep macrumors 6502


    Feb 18, 2004
    Wilmington, DE
    Have you checked the contents of the system.log to see if by any chance the output was sync'ed out to disk before the panic? Additionally, you can disable the graphical panic dialog and return to the old style detailed panic output by setting some nvram paramters. Via either single-user or safe-boot, adjust the boot-arg parameters in nvram so disable the graphical panic and output kernel debug information to the console:

    sudo nvram boot-args="debug=0x102"
    If you happen to have another mac around, you can also do some remote kernel debugging on the panicking machine by following this guide.

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