I’m not a Mac/Apple user … but i remember people having problems with “Mavericks” (and most probably applies to Yosemite) something about SMB/SAMBA configuration,
https://discussions.apple.com/thread/5495137?start=0&tstart=0
http://cammodude.blogspot.com.au/2013/10/os-x-109-mavericks-workaround-for-smb.html
http://community.wd.com/t5/WD-TV-Live-Streaming/Can-t-connect-WDTV-SMP-to-my-iMac/td-p/622779
http://community.wd.com/t5/WD-TV-Live-Streaming/Did-anyone-update-to-OS-X-Maverick/td-p/610715
