This problem has started in the last 2 weeks. I use windows 10 on a PC with Bitdefender Total Security - and have been for over 2 years. I only use 7% of my Cloud storage and have 85% of hard disk free. Get logged off BT Cloud almost daily now at different times and with no pattern to it. Becoming a real irritant as cannot find any solution.
Same problem here (Windows 10). It happened a couple of years ago (support was clueless) and started again a few days ago for no apparent reason (I delay Windows updates because they always break something). This is critical because one relies on it being "always up" and there is no warning. Now I have to keep checking the dashboard. Fortunately I have a USB backup mirrored on a NAS (for belt, braces and alternative cloud access). I am now out of contract, so considering my options. This is extremely poor.
Thanks all for posting. I'm sorry you're all having problems with the Cloud. Your best bet would be to speak with the Cloud helpdesk on 0808 100 6778.