Three times in the last five days the picture has frozen but the sound continues. It tends to happen at the start of playback of a locally recorded event, but I don't know if there are other circumstances where this occurs. Whenever it happens, changing to a different recording or to a live channel has no effect; the sound changes appropriately, but the picture remains the same. The only thing that works to fix it is to disconnect the power from the box (XG1-A? seems to be the only identification on the front of the box) and then wait for five minutes or so while the thing reboots.