This is most likely the result of having the clock source in the control panel for the FireBox set to “S/PDIF”, which means that the FireBox is trying to sync to S/PDIF digital input (the RCA type connector on the back of the FireBox). If you are not using the S/PDIF digital input you should select the “Internal” clock source in the control panel in order to achieve sync. If you do have the clock set to “Internal” and are still experiencing this problem, you should uninstall the FireBox drivers, reboot the computer, and install the drivers again (paying close attention to all instructions and any error messages that may come up). If this problem persists, you should contact tech support.