What should I do if the global hotkey does not work after enable sandbox?

There is no way to implement global hot keys in a sandboxed app )-: It would be nice if the system provided a way to do this — much like the open and save panels, it could provide an out-of-process UI for the user to configure the hot key, and thus prevent your app from knowing which specific hot key was chosen — but no sure mechanism currently exists. If you’d like to see such support added in the future, I encourage you to file an enhancement request describing your requirements.

Please post your bug number, just for the record.

One potential workaround here is for your app to provide a service, and the user can then bind a key to that using System Preferences > Keyboard > Shortcuts.

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Quinn “The Eskimo!” @ Developer Technical Support @ Apple
let myEmail = "eskimo" + "1" + "@" + "apple.com"