What a pain in the patootie! My old, trusty G4 AGP 400, which has been heavily updated and modified into a dual G4 1.2 GHz Panther beast, gave me fits when I decided to load Tiger and then update it to 10.4.3. The problem: hanging at the gray Apple screen during startup without any progress indicator (the spinning wheel). I spent the better part of three days troubleshooting this nightmare, to include two separate clean installs and migrations. I discovered lots of folks were having this issue on G4s after the 10.4.3 update around the net, but no one had any solutions (other than using another Mac in target mode to install the 10.4.3 combo updater). There had to be another way.
So, I used a safe boot (⇧ during startup) to drop into safe mode, which would work every time. Single-user mode was a no go (⌘-S); the Mac stubbornly ignored the snag. I perused the Console and kept seeing this:
Jan 9 12:37:23 Studio-Mac SystemStarter: authentication service (815) did not complete successfully
Jan 9 12:37:25 Studio-Mac SystemStarter: The following StartupItems failed to properly start:
Jan 9 12:37:25 Studio-Mac SystemStarter:
After much troubleshooting, I found that I could reboot normally once if I installed something on the machine that modified the extensions. Subsequent reboots would hang, however. The log entries above may or may not have indicated the ultimate problem. I’ll have to watch the system.log to see if they go away. After digging around in the Apple forums and other places, I found a solution for my nettlesome situation.
While in safe mode, I deleted the following files (* means delete directory contents):
After rebooting, the problem went away, even for subsequent reboots. I’ll monitor and see if installing new kernel extensions requires repeating the deletion sequence. So far, all is good for now.