At a loss here.. have installed numerous 16 ch NVR with 4MP d400 Cameras. The past few weeks I have noticed a couple things that are driving me crazy. On the live view from the NVR there are cameras that just show up as a black box until you select it as the only camera and it shows live. Secondly on the live view some cameras are freezing on live view however recording just fine. Anyone else have same issue or a solution?