One conversation, read closely.
Checking whether this app can reach your message history.
- Open System Settings, then Privacy & Security, then Full Disk Access.
- If Messages Lens is already in the list, select it and press − to remove it. The app was rebuilt, so the old entry no longer matches.
- Press +, choose Messages Lens from your Applications folder, and make sure its switch is on.
- Quit Messages Lens completely, then open it again.
Nothing is uploaded. The app reads a copy of the database on your own disk.
Reading the conversation.
Messages Lens has stopped.
Nothing is running and the port is free. Open the app again from Applications whenever you want it back.