If a user only started with a few cameras rather than the full amount of the card capacity. installers may limit the port, so that only the cameras that are active will fill in the screen. Once you need to add more cameras please verify the limit port and confirm that your card can take more cameras. 1) Configure --> Camera/ Audio Install Missing camera check box 2) Check the limit port that it might be setup to a lower number. (Note: Some model of card might not support more cameras.)