swift-Xcode7.x，7.1,7.2,7.3新建playground运行不能运行

swift-Xcode7.x(7.1,7.2,7.3)新建playground运行不能运行

Unable to find execution service for selected run destinatio

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

see:

• http://www.jianshu.com/p/0a406d50ecfd
• http://blog.163.com/nijino_saki/blog/static/800921442015112843417792/
• http://blog.csdn.net/youtk21ai/article/details/50259253