How to resolve the Leopard Blue Screen of Death

October 27, 2007 by Ross McKillop

This came as a shocker to me, mainly because I have done uncounted OS X upgrades in the past with only very minor issues mainly to due to some accessory drivers. But tonight while upgrading my friends 24 inch iMac 1st generation we had a biggie of a problem, the blue screen of death that did not go away no matter how long we stared at it. We tried resetting the PRAM and booting into Single user mode and running FSCK repairs but nothing seemed to help. So we booted up his IBM laptop and had a look on Apple’s forum, it seems 8000 or more people where interested in the same thing - as the post for “Leopard Blue Screen Freeze” was a very popular one to say the least! After searching through many of the posts we found one that looked worth trying and like an angle of mercy it worked! On our next reboot we where in to Leopard, phew! Well here is a cut and paste from the actual post, if you are experiencing this problem give this a try and I really hope Apple fixes this because it is very unlike any Apple update I have experienced in the past.

The Leopard Blue Screen of Death Fix:

“I had the same blue screen hang but the instructions below fixed it for me”.

Reboot into single-user mode (hold Cmd-S while booting machine)

Follow the directions OSX gives you when you get to the prompt (I think these were them - just type the two commands it tells you to):
fsck -fy /
/sbin/mount -uw /

Remove the following files:
rm -rf /Library/PreferencePanes/ApplicationEnhancer.prefpane
rm -rf /Library/Frameworks/ApplicationEnhancer.framework
rm -rf /System/Library/SystemConfiguration/ApplicationEnhancer.bundle
rm -f /Library/Preferences/com.unsanity.ape.plist

Exit, to continue booting normally

Update: Looks like the program Application Enhancer APP is the likely source of this problem, so make sure to uninstall it before you do a Leopard Upgrade!

To uninstall Application Enhancer - open your System Preferences and in the Other section will be the icon for Application Enhancer (assuming it’s installed). Click it and then select the Troubleshooting tab, next click the Uninstall Applications Enhancer tab.

This post was originally authored by Mike Kaye