The same problem can occur with update 10.4.10 and 10.4.11 and the same instructions can be used to resolve it. See Update9 below.
Today I tried to install the 10.4.9 update for MacOS X that
Apple has just released. Unfortunately something went wrong when installing the update and I got an error message saying that the installation was unsuccessful and the installer was moved to the Trash. After that I was prompted to restart, because of other updates.
So I restarted my MacBook Pro and let it run for some time. When I came back a bit later (at least 10minutes after the restart), I found the computer stuck at the blue screen, that appears just before the login screen comes up.
In hopes that another restart will fix everything I powered off the notebook and started it again. This time it got stuck on the gray screen with the Apple logo and a wheel spinning forever:

I tried the verbose mode:

As well as single user mode:

But both of them were unusable with this an error message appearing on the screen:
Load of /sbin/launchd, errno 88, trying /sbin/mach_init
Load of /sbin/launchd failed, errno 88
Fortunately I managed to fix this and this is the way to do it, just in case more of you get stuck with this issue:
"/Volumes/YOUR_HDD/usr/bin/open" \
/Applications/Utilities/Installer.app \
"/Volumes/Mac OS X 10.4.9 Combined Update (Intel)/\
MacOSXUpdCombo10.4.9Intel.pkg"
- Restart your computer when prompted
- Delete the dmg file
Credits go to Mike Brooks who inspired me with his post in
a forum discussion.
It seems that I'm not the only one who's
having this problem. I wonder what is triggering this and why only certain users are experiencing these difficulties.
UPDATE: It seems that Apple doesn't like any discussion on this topic as two threads (
1st,
2nd) on Apple forums discussing these issues were deleted/blocked by forum administrators. Come on Apple, that's lame!
UPDATE2: Some users claim that this issue is caused by
messed up disk permissions. It is not a bad idea to repair your disk permissions before (and after) installing an update. I wonder why this procedure is not executed automatically before the system update.
UPDATE3: Many people are having problems with all the backslashes and forwardslashes in the commands, so I got rid of most of them by putting paths into quotes. I hope this will make it easier for people not used to working in the Terminal window.
UPDATE4: Apple
has contacted me regarding this issue.
UPDATE 5: A friend of mine pointed me to
this blog entry that provides a possible explanation to the software update issues.
UPDATE 6: Some users pointed out that you can fix a broken Mac by starting the computer in the target mode (requires second healthy Mac), running the update and selecting the broken Mac as the installation destination - this bypasses working with the terminal, which some users found difficult.
UPDATE 7: According to experience of some users, PowerPC Macs can't read usb drives formated as FAT. That complicates the recovery process quite a bit :-/
UPDATE 8: I put together a small shell script that runs all the command for you - no more pain for "average" users who don't live on the command line.
Download the script, read the instructions in it, run it and provide feedback.
UPDATE 9:This issue happened to at least one user during upgrade to 10.4.10 (see comments for
this blog entry). The same instructions resolved the issue - just replace MacOSXUpdCombo10.4.9Intel.dmg with MacOSXUpdCombo10.4.10Intel.dmg.