A few days ago, a message appeared on screen saying I had to update BT Cloud. I went to make tea, came back and the screen was on my desktop page with the BT Cloud icon missing. I looked in the list of Cloud sites (BT Cloud for personal items, One Drive for work) BT Cloud was missing from there too. I continued working (wondering what to do next) and then thought to log into BT Cloud via Google Chrome. The work I had just done was there but none of the storied items from before update. Helppppp! Important stuff lost.
The app is very much broken, see https://community.bt.com/t5/Broadband-Extras-Apps-from-BT/BT-Cloud-Won-t-Start/m-p/2134725#M42399 but btcloud.bt.com should work from a browser
It does seem to be broken.