# Ensure all possible clients of CoreSimulatorService are no longer running:

killall Xcode 2> /dev/null
killall Instruments 2> /dev/null
killall 'iOS Simulator' 2> /dev/null
killall Simulator 2> /dev/null
killall 'Simulator (Watch)' 2> /dev/null
killall ibtoold 2> /dev/null
killall simctl 2> /dev/null
# There may be others

# Kill the service itself
sudo killall -9 com.apple.CoreSimulator.CoreSimulatorService

# Remove all the data and logs
rm -rf ~/Library/*/CoreSimulator