I have find a way to fix the bugs , see more in https://github.com/Alamofire/Alamofire/issues/3258 The way by jshier commented on Jul 21, 2020: Actually, it looks like adding the framework again doesn't add it to any targets, but the build still works. Adding it to the watch extension does break the build in general. You can manually work around the linking error by adding -framework CFNetwork to the "Other Linker Flags" setting on your extension target. As I relink the CFNetwork, app can run in iOS 12 device. But this is still a bug, can Xcode fix the bug?