"

 Name 

Microsoft lists the name as Groove Music in several sources, a name that has been repeated by several news sites:

 WinBeta
 WMPowerUser
 Gotta Be Mobile
 This is XBOX
 Inferse

Also note that the image used on all news sites (even the one that don't call it Groove Music) use the image that reads ""Welcome to Groove Music"", so I suggest renaming the page.   "