Xcode7.3.x运行Playground报错

用Xcode7.3.x新建playground界面直接报错
Unable to find execution service for selected run destination

解决方法1.关闭Xcode
2.在终端执行两行代码

rm -rf ~/Library/Developer/CoreSimulator/Devices

killall -9 com.apple.CoreSimulator.CoreSimulatorService