I have a separate USB WD My Book 1 TB Hard Drive. I would like to add it to the My Cloud: Mirror 3 TB unit via the USB connection. Other than plugging it in 
are there concerns and will it show up in the dashboard?
No concerns beyond having a compatible file system such as NTFS, FAT32, or HFS+.
Yes; it should be listed in the Dashboard under USB Shares.
I have 2 WD MYBOOKS and a 4TB and a 2TB. when I plug in the 4TB, all is good, but when I add the 2TB then I can’t access the dashboard.
I have to unplug the 2TB, to make any dashboard changes
What is stored on the 2TB?
I’d wonder if the MCM is indexing something on it (pictures, movies, music etc) which is taking up all the CPU’s rather limited processing power. In that kind of scenario it can’t spare enough brains to support displaying the dashboard sometimes.
Well, I’ve spent countless hours trying to get it to work, to the point where all of the disk activity on the MCM and the MB’s has stopped, waited an hour, and still no go. The WD utilities don’t see the IP address of the device at all. It just DOES NOT work.
