Upgrade from 2TB to 4TB? And factory reset

My Cloud OS 3 Personal & Network Attached Storage My Cloud
5

Folow the instructions here. http://community.wd.com/t5/WD-My-Cloud/HDD-Replacement-Single-Drive/td-p/786203 I took off my 4tb disk and inserted a 500gb (just for torrent downloading) and it worked like a charm. Of course, it’ll work with a 4tb disk