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HT1564: OS X: What is Safe Boot, Safe Mode?

Learn about OS X: What is Safe Boot, Safe Mode?

HT1564 What specific kernel extensions are considered essential?

1243 Views 8 Replies Latest reply: Mar 3, 2013 1:36 PM by il biggo RSS
benjackson Level 1 Level 1 (10 points)
Currently Being Moderated
Oct 22, 2012 5:14 AM

I want to manually find out what's causing a problem - redcine-x exports fine in safe boot mode, but not in normal mode, but i can't figure out what it is.


It's not any login item or anything in startup items in library (or font - any of the other things safe mode disables). It's a specific kernel extension that's been installed (in system/library/extensions) but i can't go thru one by one - each test in redcine-x takes 20 minutes at least (before it kernel panics), plus many are required and would prevent the computer from booting if i removed them.


what's a list of REQUIRED kexts that i can leave in there and remove all the ones that safe mode disables? or what's the list of kexts that safe mode disables?


I've been looking everywhere for this but nobody seems to care what safe mode actually disables from the extensions directory....


Any ideas?


EDIT - i answered this myself. You can do to about this mac then system profiler or whatever it's called now and get a list of loaded extensions there. Compare it to the list in safe boot and there we have what i need. now i'll remove the extensions safe boot disables and go from there in standard trouble shooting tactics. i remember conflict catcher on os 8 and 9 - ahh those were the days.


Message was edited by: benjackson

Mac Pro, OS X Mountain Lion (10.8.2)
  • Sam Katz1 Level 2 Level 2 (190 points)



    Your hard drive is failing. If an fsck fixes it temporarily your hard drive is failing.

  • Sam Katz1 Level 2 Level 2 (190 points)

    It is hard to help someone as technically competent as you.


    But Apple's preferred way of testing hardware is called the apple hardware test.


    It runs at boot time, so is not OS dependent, and can be run in a loop over night to catch memory problems, intermittent problems and the like.


    How you get to it varies by model:



    There are a few tricks here:


    1. A negative on the AHT or on RAM testers does not indicate the lack of a problem.

    2. You may want to loop the test and run it overnight. To do that, press Command +L

    3. To stop the test, press Command+. The stop button generally doesn't work.


    Regarding input managers, they are a little hard to get to. I found Cleanmymac very useful for finding the troublesome Chax input manager. For the record, you should never knowingly install an input manager, input method, or third-party kernel extension unless absolutely essential for your operation. I am also not positive Chax was causing my issue (fan running excessively due to high temp readings) because istat was controlling the fans without my realizing it. (default settings.) This is bad behavior for a monitoring application.



  • il biggo Calculating status...

    I'm in the same situation right now, an iMac G5 that shows on-screen artifacts (HUGE ones) whan booted normally, but works as a charm in safe mode. I'll try kext wizard and/or your extensions-pruning procedure.
    Thank you very much, I was starting to think I was missing some obvious information, so in a way it's nice to know that it's Apple's fault and not user stupidity


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