You can use Zune DRM (Digital Rights Management) protected music and Zune Pass with CasaTunes, but it does require some additional steps to accomplish this.

As you are probably aware, CasaTunes uses the media library from Windows Media Player (and MCE) to discover the music that is available for playback.  Unfortunately, Zune uses it’s own proprietary media library, which is not compatible with Windows Media Player’s library.  Fortunately, it is fairly easy (and painless) for Windows Media Library to detect when Zune has downloaded new music and to update it’s own media library, so that CasaTunes can have access to the new music.  In addition, CasaTunes support for Windows DRM allows CasaTunes to playback DRM protected music from Zune.

In order for Windows Media Player to update it’s own database with the latest Zune music:

1. Make sure to setup your Windows Media Player (or MCE) to monitor the music folder where Zune is configured to download it’s music.
2. If you are not running MCE, then keep Windows Media Player running (you can minimize it), so that it will continue to monitor any Zune downloads.
3. If you are using Zune Pass, you will also need to keep the Zune application running (you can minimize it), so the Zune application can automatically renew any expired leases when requested to do so by CasaTunes.
4. Finally, do not forget to refresh the CasaTunes media library to add any newly downloaded music to the CasaTunes media library.

By following these simple steps you can access an endless collection of music using your Zune subscription.