I was pointed at this mailing list to try and figure out what seems to be a pretty bad launchd bug. I recently added an opentsdb formula to homebrew, including a launchd plist. However when I load the plist with launchctl load ~/Library/LaunchAgents/homebrew.mxcl.opentsdb.plist my system hangs, then kernel panics, then on reboot it just hangs and doesn’t ever finish booting, requiring me to boot into single user mode, fsck the filesystem, mount the fs as read/write and then delete the plist. This is 100% reproducible on my MacBook Pro (Retina, 15-inch, Mid 2014) running OS X 10.11.5 (15F34). Steps to reproduce (warning, this will almost certainly cause a kernel panic): /usr/bin/ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)" brew install opentsdb ln -s `brew --prefix hbase`/homebrew.mxcl.hbase.plist ~/Library/LaunchAgents/ ln -s `brew --prefix opentsdb`/homebrew.mxcl.opentsdb.plist ~/Library/LaunchAgents/ launchctl load ~/Library/LaunchAgents/homebrew.mxcl.hbase.plist sleep 15 && launchctl load ~/Library/LaunchAgents/homebrew.mxcl.opentsdb.plist Note that running hbase via launchd and starting opentsdb manually does not cause a kernel panic (or any other problems that I’ve noticed). Does anyone have any ideas about why this is happening?