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Hz_UK Level 1 Level 1 (0 points)



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)
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