您执行的分步指南实际上对我有所帮助，现在我可以使用xcode 10.2.1来处理iO 13.唯一的区别是，我从此github ，因此您可以尝试此操作.然后我重新启动整个Mac，以确保:)

your step by step manual you performed actually helped me and now I can work with iOs 13 with xcode 10.2.1. There is only difference, that I downloaded device support files from this github, so you can try this. And I restarted whole mac to be sure:)