Tips: Mac OS X: Troubleshooting a Boot Failure

I had a major trouble after installing a system extension on my Mac OS X 10.4.7 installation last night. After configuring and installing the extension called Callisto Build 008, the Mac OS X failed to boot on restart.

The usual Apple screen showed up but after a while a nice error screen was presented demanding me to press the Power Button to shutdown the computer.

I was so frustrated fearing that I need to format and reinstall the OS from scratch without having backed up my work data.

I believe there must be a solution to this...that doesn't require me to reformat the hard drive. In Windows case, I can use the installation CD to access the hard drive and manually fix the problem. I'm expecting the same thing on Mac OS X -- to enter a command-line text interface and manually remove the offending system extension.

I went ahead browsing my favorite Insanely Mac forum and found an interesting thread as a starting point. Here's my actual procedure to fix the problem:

1. Use F8 and enter boot option -v -s


2. Text-mode command prompt will show up


3. At root# prompt, enter /sbin/fsck -fy


4. OS will check the boot disk, to make sure we're not working on a screwed up hard drive


5. At root# prompt, enter /sbin/mount -uw / to mount the hard drive in read+write mode


6. Then, cd /System/Library/Extensions
   
7. The system extensions I just installed were Callisto.kext and CallistoHAL.kext, so I removed them by
   
   rm -rf Callisto.kext and
   rm -rf CallistoHAL.kext
   


8. At the root# prompt, enter the command exit


9. OSX will continue to boot and successfully enter the GUI mode

Keywords: mac-os-x, troubleshooting