More than 18 million households with Freeview will need to retune their set-top boxes and TVs later. The service is being upgraded to give more homes channel Five, while those that did get Five will find themselves unable to watch it until they retune.
Many BBC News website readers have already tried to retune and encountered problems.
I retuned my Freeview TV earlier. Before the retune I had over 30 channels. Now I only have BBC 1, BBC 2, BBC 3, CBBC channel, BBC News and BBC Red Button. I have lost nearly all my channels now!
Armand Derri, London
We gained Five but lost ITV 3. We are very annoyed because we have lost a lot of our favourite programs!
Maurice Short, Brighton, E Sussex
I am constantly getting the message telling me to re-tune but when I do I lose some channels. Sometimes they come back, sometimes not. What I find annoying is that I had no trouble until the current update programme started.
A Boydell, Briport, Dorset
I have gained the unwanted Five and lost ITV 3, which I watched occasionally. But why lose ITV 3 when there are all these shopping channels?
Adrian Worsfold, New Holland
I've retuned my Freeview TV and have lost all BBC channels except BBC 4. This cannot be correct? Unable to find channels 1 - 8 and therefore unable to manually tune them in. Why has this happened?
Sonia Meah, London
I have a fairly new Freeview digital TV and successfully retuned it yesterday. Unfortunately I now have such a poor signal on ITV 1 and Channel 4 that they are totally unwatchable.
Sue Hoad, Brighton, East Sussex
After the previous switchover BBC channels suffered a lot from freezing. I have just retuned again today and the problem is still there. This problem did not exist before the switchover and only BBC channels seem to be affected.
Dave Joslin, St Austell
Up until today I had good signal strength for Five from the Reigate transmitter. After the retune I have no usable Five signal. Such is progress!
Andrew Guest, Crawley
We have never had any trouble with Five but after the retune we now have a picture but no sound. We were better off before!
Sara Laverty, Ashby de la Zouch
Last time I had to retune Freeview, three recent model Freeview Daewoo VCRs failed as they did not support the updates. I've yet to take them to the recycling centre as I can't yet bear to chuck out all that expensive technology, even though it's obsolete.
Simonides Mehta, Poole, Dorset
My Freeview box has stopped working....more cash to shell out then!
PROBLEMS GETTING HELP
I have lost ITV 3 since the retune, apparently permanently. It is there but it's so distorted it's unwatchable. I complained to OFCOM who blame Freeview, who are not accepting calls due to 'high call volumes'. I've certainly lost out on this reallocation of channels.
Hamilton White, Lochaber, Scotland
Some areas including mine do not have full cover from the first switchover. Digital UK helpline is less than useless and engineers in the area are charging huge fees to come and help. Unscrupulous retailers are saying that they do not stock the necessary equipment and a call-out is necessary.
Michael Mead, Ambleside, Cumbria
Earlier I tried to access the recommended website at
but all it said was "This website is experiencing high amounts of traffic and is currently unavailable. Please try again later." Not a great start!
Jerry, Wokingham, Berks