This is a fairly common problem and it does not indicate that your data is about to be lost, although I’m sure you know the value of having a backup. Anyway, first thing to do is detach any USB drive you have connected to the MyCloud, then do a 40 second reset using a paper clip in the reset button at the rear of the unit. Once it has re-booted you should be able to get access to the dashboard. It may take several attempts.
Please check your USB storage on a computer for any errors. Connect this back to your MyCloud once it has stabilized. Always make sure to eject your USB drive through the dashboard before re-booting or restoring the MyCloud.
Your problem with the Twonky settings being over-written is a known problem with the implementation of Twonky on MyCloud. You better read about it here: http://community.wd.com/t5/WD-My-Cloud/FAQ-Twonky-DLNA-Media-Server-Setup-amp-Use/td-p/858810
