Firmware update 2.30.165 is not good for Mac OS X

Legacy Products My Cloud OS 3
2

How is your Mac connected to the My Cloud, using AFP or SMB (or some other format)? It is possible the SMB 3.0 update the latest firmware came with is causing a problem.

You may want to see the Firmware 2.30.165 discussion thread to see if anything mentioned in there applies.

http://community.wd.com/t/firmware-2-30-165-discussion/202238/