However, I for some reason, after the installation ... my SIP is disabled. I have been trying over and over again to put my computer into Recovery mode, but I keep getting the Prohibitory Symbol ... any suggestions of what I can do to reengage my SIP?

  • Wait, isn't the Prohibitory Symbol indicating the SIP is enabled? Have you perhaps installed any unsigned kext (i.e. drivers) before the update? That would explain why your machine doesn't boot. SIP is on and thus prevents the boot due to the conflicting kext. Or am I missing something here?
    – Gero
    Nov 21, 2018 at 14:38

1 Answer 1


Boot the system in internet recovery mode to enable SIP. You can do that by holding down Option-Command-R while powering on the iMac. After booting, follow instructions similar to ordinary recovery mode to enable SIP. I.e. open a Terminal and execute:

csrutil enable

If you haven't got internet recovery on the iMac, you will need to install the updated firmware software that is available for your model first.

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