I am having problems with sound sync. Sometimes when I switch on, it's completely out of sync. The TV is connected to the box by HDMI. If I reset the box which takes ages, it corrects itself until the next time. I have checked all the sound settings advised in these posts, but doesn't seem to make any difference, just have to keep re-booting the box!
Haven't connected to another tv as it's upstairs and I'm an OAP so i can't move it. The box has not been replaced, and I'd rather not go down that route if possible as there are a lot of recordings on it. It only happens occasionally but very frustrating.
I've swapped the HDMI ports but I don't know if it makes any difference because the problem is not there all the time, so it's very difficult to know. At the moment it's on live TV. Seems to be ok on apps, but it happens infrequently so it's going to be difficult to diagnose. Thanks for your interest.