解决Xcode模拟器attaching卡死问题 .

1.Command-Option-Shift-K to clean out the build folder

/Users/apple/Library/Developer/Xcode    （注：Library资源库是隐藏的文件夹）

里面有DerivedData和Snapshots两个文件夹，删除里面文件即可(命令行rm -rf *)

2.(Xcode 4.2 will show you the Derived Data folder: choose Window > Organizer and switch to the Projects tab. Click the right-arrow to the right of the Derived Data folder name.)

In the simulator, choose iOS Simulator > Reset Content and Settings.

3.Product -> Edit Scheme->Debugger 选择GDB