I've just got myself a Samsung 4k UE43RU7100KXXU to go with my BT 4K YouView box only to find they're not compatible.
The TV simply doesn't recognise the source YouView box. A lot of googling later and it appears to be a common issue, probably relating to 'HDCP 2.2 Content Protection'.
I've restarted / reformatted / tried different leads / updated firmware....etc and nothing.
Does anybody have any ideas what i can do? YouView box works fine on my other non-4K TV.
I know this is ages old, but did you manage to fix this? I suspect my issue is the same - sometimes my youview works, other times it just won't.
I gave up a long time ago and ended up downgrading the 4k box to a regular HD box just so I have something that works, no idea if the issue would have resolved itself by now i'm afraid