Thumbnails disappear when both usb-connections are in use with a 2TB and a 4TB. Please help

When two usb connections are in use with a 4TB and a 2TB the thumbnails dissapear on the 2TB. I can make them come back by connecting the hdd to the pc and remove the “wdtv folder” in the hdd. But it doesnt´t last for long - it happens again when turning the power on and off. When both hdd are 2TB the problem disappear. I have not tried 2 x 4TB, but spending all those money just to find out that the problem is still there does not sound good. Any suggestions?

Currently the WD does not support hdds bigger than 2TB. As far as I know, they are working on this issue, but if it is a hardware limitation of the inbuilt USB controllers, we’ll probably never see this solved.