All data gone on My Book Studio II

WD External Drives External Drives for Mac
3

I don’t think it is Mavericks problem as I was testing OS X 10.9 (on separate partition on my mac) since June and had zero problems with peripherials in all beta versions, and finally installed the GM on main system partition a week before the disaster with My Book Studio II happened. So, I was already running 10.9 GM for at least a week without problems with my WD My Book Studio II unit. My mac shuts down automatically every day at 05:30 after performing overnight backups and cloning, then restarts afresh at 05:50. During that week I also have restarted my mac manually numerous times, mainly due to other software being updated to Mavericks. So, if it would be Mavericks fault it would have happened at the first restart, not about 30 restarts later.