Why can't I enable launching Simple In/Out at login?

macOS

If you're on macOS and you're trying to enable launching Simple In/Out Desktop on system startup, you may see this error when toggling the setting:

This is most likely because the app doesn't have the system permissions needed to modify system settings needed to add Simple In/Out to the login items. Update the security permissions in System Preferences:

1. Launch System Preferences from the Apple () menu from the upper-left corner of your screen
2. Click Security & Privacy from the available options
3. Click the Privacy section at the top of the window
4. Scroll the left side to find the Automation option
5. Check the box for System Events.app under Simple In Out.app