You can use pretty much any HDD (non SSD) in a single bay, single drive WD My Cloud enclosure. Personally I’ve successfully experimented with a number of different SATA HDD (WD Green, Blue, Red, white label HGST, and one from Seagate) in a first gen single bay My Cloud enclosure. The single bay My Cloud unit may have a limit on the maximum capacity however. Its possible drives over a certain capacity (I think it might be 16TB or larger) may not show their full capacity once “unbricked”.
However, due to the age and limitations of the single bay My Cloud units, especially the OS3 limited first gen single bay My Cloud, one may want to seriously consider investing their money in a better NAS enclosure. There are several other manufacturers to choose from (Synology, QNAP, etc.) that offer single and multi bay NAS units. WD seems to be slowly ending sales of the My Cloud line of NAS units. Do not bother with the My Cloud Home line, they are not real NAS devices.
