问题
xcode 9 simulator error unable to boot the simulator launchd failed to respond mac os sierra
I ave tried deleting contents from derived data, restarting Xcode , Uninstall and install of xcode etc.
回答1:
In this case, launchd is crashing when trying to launch.
This could be as a result of deleting the /private/tmp folder.
To resolve this, I typed the following commands on my terminal:
sudo mkdir /private/tmp
sudo chmod 1777 /private/tmp
回答2:
Restarting Mac solved it for me.
来源：https://stackoverflow.com/questions/46487099/xcode-9-simulator-error-unable-to-boot-the-simulator-launchd-failed-to-respond-m