Why would you want to do any copying from within the My Cloud app?? I have never even installed that app.
There’s two ways of doing it…the easiest but also much slower would be to go to Windows My Network → EX4 → Name of your USB drive shown as a folder → Open it and select the files/folders you want to copy → Also open the folder with share name on EX4 where you want to copy these files to → Drag and drop them there.
But be aware this could be a long and slow process if it’s a lot of data, esp. if you are using a wireless connection on your Windows laptop/desktop. The reason and the alternate faster way is briefly described in this thread → http://community.wd.com/t5/WD-My-Cloud-EX2/Very-slow-transfer-speeds-even-when-external-drive-is-connected/m-p/770565
