升级XCode到10.3时报错，错误信息如下：
: error: Failed to find a suitable device for the type IBSimDeviceTypeiPad2x (com.apple.dt.Xcode.IBSimDeviceType.iPad-2x) with runtime iOS 12.4 (12.4 - 16G73) - com.apple.CoreSimulator.SimRuntime.iOS-12-4
Failure Reason: Failed to create new simulator device that matches IBSimDeviceTypeiPad2x (com.apple.dt.Xcode.IBSimDeviceType.iPad-2x) for runtime iOS 12.4 (12.4 - 16G73) - com.apple.CoreSimulator.SimRuntime.iOS-12-4 (Invalid runtime: com.apple.CoreSimulator.SimRuntime.iOS-12-4)
Underlying Errors:
Description: Invalid runtime: com.apple.CoreSimulator.SimRuntime.iOS-12-4
最终在*上找到了解决方案。
方案一：
重启MacOS电脑，问题就不知道什么原因就解决了。这是很粗暴直接的方式。
方案二：
kill掉模拟器进程，命令如下：
$ sudo killall -9 com.apple.CoreSimulator.CoreSimulatorService
接着设置xcode path：
$ sudo xcode-select -s /Applications/Xcode.app/Contents/Developer
如果还不行，重启模拟器
$ xcrun simctl erase all
参考：https://*.com/questions/57155654/xcode-10-3-installation