This issue is well discussed in numerous prior threads (see links below). One can use the WD “Quick View” taskbar icon that gets installed with certain WD programs to issue the shutdown command. Other options are explained in the threads below.
http://wdstagingsplit.staged-by-discourse.com/t/where-is-my-shutdown-button-in-admin-panel/175229
http://wdstagingsplit.staged-by-discourse.com/t/safe-shutdown/147307
http://wdstagingsplit.staged-by-discourse.com/t/i-cannot-shut-down-my-wd-8tb-with-all-any-way/174439
http://wdstagingsplit.staged-by-discourse.com/t/how-to-safely-shutdown-mycloud/155265
