@gws3
Not much consolation for you I know, but I have switched off and stored three different YouView boxes over time, and all of them have come back intact.
Your problem looks like a failing box, probably coincidentally with the home improvements.
In general, if a box loses recorded programmes, then nothing short of a factory reset will bring it back to working properly; and depending if the fault was a genuine one-off, or something likely to recur, it may not last and carry on working correctly afterwards.
You don’t say which YouView box it is, but I’m assuming it’s not a Pro box under subscription. (If it is, contact BT Help and they will remotely diagnose it for you, and possibly replace it, depending on what they find).
But for any other sort of YouView box, try the various Maintenance Mode resets found here:-
https://www.bt.com/help/tv/fix-a-problem/tv-boxes/how-do-i-reset-my-bt-tv-box-
Choose the procedure for your model of box, as it can vary slightly from model to model.
Start with an Option 2; if that works, do an Option 4.
But if it doesn’t restore normal operation, apart from the 90% recordings that are likely lost anyway, then there is nothing for it but an Option 5.
This should get it back working if this is possible (it may not be, if you have a hardware fault), but keep a close eye on it in the near future, to see if it does it again.
There is a possibility that even with you selecting Option 2, the box will do an Option 5; YouView boxes that know how sick they are, and that the chosen Option won’t cut it, are likely to do this. This is not a fault; but be aware it may happen.
Do please let us know how you get on (and what model of box it is).
*** Longtime YouView box owner, BT Broadband customer, but never a BT TV subscriber ***
