An interesting thing happened to my wife yesterday. She was working on her Macbook when the power cord happened to disengage, turning off her computer (her battery has been shot for a while, so this is a fairly common occurrence). When she plugged it in and powered back on, her computer stopped at the splash screen, threw up a prohibitory sign, and eventually rebooted. It was a sick loop.
A brief bit of research revealed this problem as a variation of kernal panic (the Windows equivalent is the Blue Screen of Death, which I’m intimately familiar with). I don’t use a Mac. This was new to me. And kind of exciting.
First, I tried booting into safe mode. It didn’t work. Then I tried resetting PRAM. Nothing.
There was clearly some kind of disk error going on. I don’t know if a system file became corrupt (or deleted) or a piece of hardware is failing. My primary focus became saving the contents of the hard drive.
Linux to the rescue. Using my Linux machine, I created a live CD of the Knoppix distro, which is a simple operating system with a nice user interface that has a lot of recovery features built in. I started the computer and put the live CD in the drive. After the boot chime, I held down the “option” button to get to the boot screen. I chose to boot from the live CD instead of the Mac hard drive. Knoppix gave me unfettered access to all the Mac’s saved files, which I was able to copy to portable storage.
Hard drive content saved. Stage one complete.
My next goal was to run the Mac native recovery tool. Since I couldn’t get there by normal means (through safe mode or the boot screen), I decided to create an OSX install disc. I downloaded a copy of Snow Leopard, created a bootable USB from the .dmg file using TransMac (two week free trial), plugged it in, and fired up the machine. I, again, held down “option” to get to the boot screen, but this time opted to boot the new OSX installer.
This allowed me to run a disk repair on the hard drive. While it did, in fact, discover a couple of errors, this did not solve the problem. After rebooting, the computer was still unable to boot from the hard drive.
So, as a last resort, I booted back into the OSX installer, reformatted the drive, and did a clean install of Snow Leopard.
If you have read to this point, you probably happened across this post through a Google search. I hope it helps. Understand, though, that I am not a Mac user and am not responsible if your attempt to duplicate my efforts ruins your computer. 🙂