Microsoft’s music service Groove (formally known as Xbox Music) has a music subscription plan where you can subscribe and then listen to music from their collection on your Windows 10, Windows 8.1, Windows Phone, Android, Xbox and iOS devices via the Groove music apps. A Groove Music pass gives you access to millions of songs from Microsoft’s collection and you can stream any of them to your devices via the Groove apps. You can also download music for offline playback on your devices but there is a limitation of only having four registered devices that you can download music on at any one time.
Note: This is not the same as downloading music from your personal collection stored in OneDrive’s music folder. There is no limitation on the number of devices with OneDrive music.
When you have a Groove music subscription and you download a song the app automatically registered your device and then you can download any music from Groove. The device could be running iOS, Android, Windows Phone, Windows 8.1 or Windows 10. After you have downloaded music on your fourth devices you will not be able to download on an additional device. If you want to add an additional phone, tablet or PC you can remove a device using the Music device manager page at Account.Microsoft.com or via the Manage my devices link in the Groove app settings.
When you open the page it lists registered devices with the device name, device OS and when the device was first used with Groove. From this page you can remove a device to make space for a new one by clicking on the Remove link, once you remove it you will no longer be able to listen to music offline with it but you will still be able to stream music.
There is a limitation that you can only remove one device every 30 days and as I said above streaming is not part of the four device limitations, neither is downloading of your personal music collection from OneDrive’s music folder.