I just found a big bug.
I have Wd My Clud 4T fully working attached to the network.
I configured a powered USB 2.0 hub with 7 slot ports that I connected to the USB port of my white WD My Cloud; I attached 3 Hard Disks to this hub.
When I connect the hub My Cloud starts analysing it, it recognized 3 Hard Disks on 4 and after some minutes it does not reply anymore to web interface (disconnected? crashed?).
Please advise how to fix this issue.