On my iMac with HIgh Sierra 10.13.6 the update would notinstall and I could not restart my computer until I restored it from a backup disc. Has anyone else had this problem?
How can install this security update on HIgh Sierra 10.13.16 when it will not start up when I try to install it. This is Security Update 2020-005 10.13.6. The computer will not restart and gives an error message saying I should close the installer.
iMac 21.5″, macOS 10.13