How to Resolve the Leopard Blue Screen of Death

This came as a shocker to me, mainly because I have done uncounted OS X upgrades in the past with only very minor issues, 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, 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 were interested in the same thing because 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 worthy of trying and like an angel of mercy it worked! On our next reboot we were into 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”.

  1. Reboot into single-user mode (hold Cmd-S while booting machine)
  2. 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 /
  3. 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
  4. 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

Comments [13]

  1. Thanks it works!! Yes and before i installed the app enhancer which caused blue screen of death.

  2. Oh man u saved my life. Thought my powerbook had seen its last day then boom (in voice of john madden)! We're back up n running in no time.

    I'm most gracious for the assistance.

  3. fsck -fy /

    /sbin/mount -uw / typed in that, but how to i remove the files that you suggest? i can't see them to remove, im using snow leopard btw



  4. I am not that familiar with single-user mode so how do you remove those applications?

  5. Ok I tried it and it said:

    rm: illegal option — /

    usage: rm [-f l -i] [-dPRrvW] file …

    unlink file

    What do I do now?

  6. Thank you for this, it helped me alot, just an FYI, the command is
    /sbin/fsck -fy

  7. I did this then my imac got stuck on SATA Warning:completing a zero block transfer

    What should I do now?

  8. Thanks for this. It worked beautifully! Those trying it should note that to remove the 4 files, leave a space after rm and after -rf . So, for example

    rm SPACE -rf SPACE /Library/PreferencePanes/… and so on.

    After seeing that blue screen for about 20 start-button-boots, I followed the procedure outlined here and immediately got my desktop back!

    Thanks again,



  9. I did it and got no such file or directory. What do i do now?

  10. I did all of these commands but the blue screen remains. I’m using Leopard. Any other solutions?

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