Solution (almost certainly): postfix fails to launch at boot

[Ryan Schmidt]

On Jan 11, 2020, at 12:32, Steven Smith wrote:

> First, as Gerben points out, macOS‘s postfix launch daemon is in /System/Library, so you’d have to disable SIP to unload it, which at best is a major PITA, and realistically a non-option.

Are you certain? Certainly modifying anything in /System would require disabling SIP, but we're not talking about modifying anything there; we're just talking about unloading a launchd plist. Whether or not a plist is loaded used to be recorded in the plist itself, but that hasn't been the case for many years; according to the launchctl(1) manpage, that state is now stored "elsewhere on-disk in a location that may not be directly manipulated by any process other than launchd."