Difficulty deleting / moving files around, once they're on 2TB MyCloud NAS

I had this same problem out of the box (not using Transmission or anything non-stock). Setting a user password seemed to help for a bit but strange security related things kept happening. It got worse:

http://community.wd.com/t5/WD-My-Cloud/Trouble-Moving-Files-Folders-Within-A-Share/td-p/619091/highlight/false