This was a notorious problem which affected many ondigital viewers and as far as I am aware has never really been resolved with the introduction of Freeview. We can't get cable in our area and had subscribed to Ondigital before it went into liquidation and so kept our set top box. We kept saying that we would get Sky installed but have never quite got around to it and instead just subscribed to topup tv because we don't have much time to watch tv anyway. It was mainly for the kids. Unfortunately , we still keep getting screen freeze problems every so often , black screen with red dot (aerial problem) or scrambled picture a lot. I've never known Ondigital/Freeview to be trouble free.