I deleted libsystem.B.dylib by mistake. On boot it got struck with Apple logo and a loading symbol below it. I tried booting with Cmd-v but it got struck with

AppleIntelCPUPowerManagement: initialization complete
[HCIController][configurePM] power parent ready after 1 tries

and didn't process any further.

Any hints on how to get out of this are appreciated!


Roh oh. You'll need to find someone with a copy of it (what Mac have you got?), then copy it back over somehow, probably by mounting the drive with another machine, then cross your fingers and hope OS X plays nice with it. If not you'll need your system disks and do a clean install.

  • How do i mount a drive from another machine? can u show me step wise solution please? – surendran Sep 12 '11 at 11:06
  • 1
    1) Use target disk mode (docs.info.apple.com/article.html?path=Mac/10.6/en/8443.html) or 2) pull the drive out of the machine and put it in an external caddy and go from there. Target disk is the easiest but you'll need another Mac to do it, external caddy means you can do it on any machine. – Nicholas Smith Sep 12 '11 at 11:42

Do you still have your Installation DVD for Snow Leopard? If yes you can just boot from DVD and reinstall the operating system. Don't forget to run Software Update afterwards to update to the latest version.


You had a Time Machine backup right? Boot from the OS install DVD with the backup disk connected and ask it to restore from the backup disk.

Otherwise follow some of the advice above and cross all available appendages.

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