If using a Mac see the existing thread (link below) discussing this issue.
WD My Cloud Mac only uploads 512 KB and then stops
It is generally recommended around these parts if connected via the local network (i.e., not remotely) to bypass using the WD apps and software to transfer files and use either Windows Explorer on Window’s OS’s or the Finder on Macintosh OS’s to copy/transfer files to the WD My Cloud (or from the WD My Cloud to the computer).
