MyCloud 3TB won't play itunes

How does the Boise app or the Bose device access the My Cloud? Does it use DLNA or some other method?

Do you see the same issue of songs missing, duplicated, etc. when using a DLNA client on your computer or mobile device (like BubbleUPnP for Android)?

If your Boise device uses DLNA to access the My Cloud make sure to read the following unofficial FAQ.

https://community.wd.com/t/faq-twonky-dlna-media-server-setup-use/95373

Depending on how the Boise device accesses and reads the media files you may need to use a metadata tagger/editor (like Media Monkey or MP3Tag) to fill in or correct any metadata tag errors iTunes made when generating/cataloging the media files.