Postfix Goofiness and Temporary Workaround

Many distributions of Mac OS X come with Postfix installed, which make for great mail servers. However, Apple added a new twist to its UNIX backend with the addition of its own pseudo-replacement for cron, called launchd. This causes a minor, yet fatal error with Postfix on Tiger. If you use the preinstalled Postfix or roll your own, you may encounter this in your mail.log: fatal: open lock file pid/ unable to set exclusive lock: Resource temporarily unavailable. To correct this you need to mod a system setting file provided by Apple, and the solution has been posted on I must say, killing launchd via HUP doesn't seem to break my system but your experience may be different than mine, so please exercise caution and restart the box if you're unsure of what you're doing.