First, please check the microscope version on the top of the model. If it's V1.1 or older, those are no longer currently supported with our software. If using the app version, make sure your device is plugged into USB port before opening the app. If you are using the xploview software version, you must check your camera privacy settings to unblock the device first, then once in software go to the gear symbol and select the microscope as it defaults to your built-in webcam.