I recently purchased 3TB MyCloud and have been having trouble keeping it up as it was getting desconnected very often and only way to get it back online was to power cycle. But after going through forums I was able to find out that we need to trurn off the SLEEP option and have Static IP.
Other issue was basically slow uplooad that I came over by first physically moving the file to external hard drive and then attach it to my cloud on supported USB and then copy to My Cloud.
I had to spent atleast 10-12 hours going over forumns and setting up. Now I think it is stable. I would have loved if WD had provided a trouble shooting wizard with suggestions, speed testing etc. in one place.