Preview members were able to get access to the UWP version of Groove Music last night – that is, the version of Groove Music that enables background music and multiple testing carried out by ThisGenGaming confirms that the feature is working perfectly and is more stable I might add than the Cast app which has been available for a few days now.
This method requires you have OneDrive. You will need to upload your .mp3 music files onto OneDrive in order for this to work.
Move your music files into the “Music” folder if you didn’t upload in to it directly.
Open Groove on your Xbox One and make sure you select the option that allows you to play your own music.
Press the pause button to open up the side menu and scroll down to settings
When in your settings, you’ll notice a button towards the top that says ‘sync’ you have to press this in order for your OneDrive music files to show up in the Groove app on Xbox One
Enjoy your own custom playlists!