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After kernel extension error, I now can't re-install snow leopard.

842 Views 17 Replies Latest reply: Feb 27, 2013 9:54 AM by Hz_UK RSS
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Hz_UK Calculating status...
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Feb 20, 2013 3:34 AM



I attempted to boot my mac up the other day and was given a 'prohibited' sign, so I re-booted into safe mode.


Once booted, I received this message when I tried to insert a flash drive:


System extension cannot be used


The system extension /System/Library/Extension/IOstorageFamily.kext was installed improperly and cannot be used. Please try reinstalling it, or contact the product's vendor for an update.


I followed advice given on another thread and replaced the extension with a time machine back-up.


The error message went away and I could use my flash drive


I then turned off my Mac, rebooted and was given the prohibited sign again.


I then tried to enter safe mode and it went so far and ground to a halt.


I tried over and over, but with no luck.


I zapped the NVRAM, reset the SMU, tried in single user mode, etc, as advised on another thread.


I did, once,  get past the safe mode task bar and got to a grey screen with an apple logo, but it remained in that state for over 20 minutes, so I rebooted and was back to square one again.


I couldn't find my original 'snow leopard' disc, so I ordered a new disc.


Try as I might, I cannot re-install snow leopard.  Thinking it might have been a hardware issue I have removed the HD and placed it into another Mac, ran a hardware test, etc, everything seemed fine.


I then thought it might have been the optical drive so using a FireWire cable, used the other mac's op drive, still no joy.


I bit the bullet, reformatted my HD, via the other mac, and tried again with no luck.


I am pretty sure it is not a hardware issue as such as I am typing this on the problem mac, as I have installed ubuntu precise pangolin, from disc, with no problems whatsoever.


I am now at a complete loss on how to proceed, as I desperately need to reinstall my mac OS, for my job as a graphic designer


Thanks in advance,



Mac Pro, Mac OS X (10.6)
  • Grant Bennet-Alder Level 8 Level 8 (48,110 points)

    Exactly which model Mac Pro do you have by MacPro 3,1 designation or processors and speeds?

    Mac Pro (Early 2009), Mac OS X (10.6.8), & Server, PPC, & AppleTalk Printers
  • Grant Bennet-Alder Level 8 Level 8 (48,110 points)

    The Mac Pro 5,1 2010 model cannot boot or install anything less than the custom 10.6.4 that shipped in the box. The "Full retail" DVD is useless, as it contains 10.6.3 at the latest.


    You need its original "shipped in the box" DVD, or to install on another Mac using the "Full Retail" DVD updated in place with Software Update to at least 10.6.5.

    Mac Pro (Early 2009), Mac OS X (10.6.8), & Server, PPC, & AppleTalk Printers
  • Grant Bennet-Alder Level 8 Level 8 (48,110 points)

    You spoke of moving the drive to another Mac to test it, and that it booted successfully there.


    a) You could install 10.6.8 on a drive installed there, PROVIDED you start from a "Full Retail" DVD (which contains drivers for every appropriate Mac model).


    b) You could do a similar operation using FireWire Target Disk Mode to use the Troublesome Mac Pro as a glorified Hard drive while installing from the other Mac.


    c) you could use this procedure, which requires an external drive to hold a NetInstall image AND a Mac running 10.6.8:


    HowTo revert new MacBook Pro, Mac Pro or iMac to Snow Leopard

    Mac Pro (Early 2009), Mac OS X (10.6.8), & Server, PPC, & AppleTalk Printers
  • Grant Bennet-Alder Level 8 Level 8 (48,110 points)

    Yes, that should work. be sure you start with a "Full Retail" DVD, since those have "Drivers for every appropriate Mac". Model-specific DVDs have drivers for only the model intended, and generally will not run another model Mac.


    Note: Apple assures us that this convention continues in "purchased" Vs "shipped with your Mac" versions of Downloaded Mac OS X. Images derived form the purchased downloads will boot and run any appropriate model Mac.

    Mac Pro (Early 2009), Mac OS X (10.6.8), & Server, PPC, & AppleTalk Printers
  • The hatter Level 9 Level 9 (58,560 points)

    Those adamant fools. The Apple tech doc for minimum OS builds:



    Can't use less than what it shipped with, and for once Apple stopped making retail available at 10.6.3 whereas OEM was "post 10.6.4" with drivers for ATI 5770 and hardware (10.6.5+ recommended as the ATI driver was buggy).

  • Grant Bennet-Alder Level 8 Level 8 (48,110 points)


    This is the applicable portion of the table from The Hatter's link above:



    Mac Pro (Mid 2012)Jun 201210.7.310.8 11D2001, 12A269
    Mac Pro (Mid 2010)Aug 201010.6.410.7, 10.7.2, 10.7.310F2521, 10F2554, 11A511a, 11C74, 11D2001
    Mac Pro with Mac OS X Server (Mid 2010)Aug 201010.6.410.7, 10.7.2, 10.7.3 (Server)10F2522, 11A511a, 11C74, 11D2001 (Server)
    Mac Pro (Early 2009)Mar 200910.5.610.69G3553, 10A432
    Mac Pro (Early 2008)

    Jan 2008


    10.5.2, 10.5.4

    9B2117, 9C2031, 9E25
    Mac Pro

    Aug 2006


    10.4.8, 10.4.9, 10.4.10, 10.5

    8K1079, 8N1430, 8N1250, 8K1124, 8P4037, 8R3032, 8R3041, 9A581, 9A3129
    Mac Pro (Early 2009), Mac OS X (10.6.8), & Server, PPC, & AppleTalk Printers
  • The hatter Level 9 Level 9 (58,560 points)

    They want us to use Lion or ML.


    They did sell an outrageous 10.6.8 + Lion on USB flash memory card for $69.


    You can order the OEM DVD for your model Mac if it did not come with one for $20?? or so fee, all they will need is you to read the serial number, something you never ever post or put online - to check.


    And I don't see much value in talking to someone that won't go beyond reading a script.


    Make sure you have AppleCare, backups, a 1500VA UPS (APC or CyberPower are excellent)

  • Grant Bennet-Alder Level 8 Level 8 (48,110 points)

    Apple expects that most folks have used the factory-installed software, kept their original DVD in a safe place for re-use, and possibly  upgraded to later versions.


    If you need a re-Install during service, you may find your Mac has been "upgraded" during service.


    There have been a number of times when the last-issued "standard" software will not boot the "last issued" Macs.


    • You can ask them to send you a copy of the Installer for your model Mac. For a nominal fee, they can send you a DVD-R of the version that would have installed on your Mac when new.


    • You can create a "recovery_HD on a [USB] stick" for your Mac, using Recovery Disk Assistant and a working Mac OS X 10.7 or later.

    Mac Pro (Early 2009), Mac OS X (10.6.8), & Server, PPC, & AppleTalk Printers
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