Sonos does not seem to index m4p music in my iTunes library. How can I fix this?

You're blaming Sonos for Apple's past behaviour?
[quote][/quote]I blame Sonos for creating an inferior product and hiding its main (huge) flaw from the buying public until after they've made the purchase. Apple's behavior has nothing to do with it..

"Hiding?"  I hardly think listing in their FAQ under "Sonos and iTunes" subheading "Playing iTunes Purchased Music" the following can be called "hiding" anything:

https://sonos.custhelp.com/app/answers/detail/a_id/626/kw/Apple+DRM/related/1

Before 2009, iTunes purchased music was copy-protected using a form of Digital Rights Management (DRM) called FairPlay. The DRM protection prevented this purchased music from being played through any non-Apple devices, including the Sonos Wireless HiFi System. The vast majority of music sold through the iTunes Music Store was protected with DRM except for a small offering of DRM-free music through iTunes Plus. During 2009, Apple did away with DRM protection and began selling all music free of any playback restriction.

All music purchased through iTunes since mid-2009 is free of DRM and will play without restriction on Sonos. Tracks previously purchased with DRM protection will remain protected against playback on Sonos.

Audiobooks purchased through iTunes with the .m4b file extension will not play on Sonos as they are DRM protected.

If I have DRM tracks in my library, can the DRM be removed so I can play them on Sonos?

The following link has all the information you should need about upgrade your DRM tracks through iTunes:
http://support.apple.com/kb/HT4914

iTunes Match allows users to remove DRM protection from any tracks in the matched library. Match the tracks with iTunes Match and remove the local copies by deleting the files. Then download the matched version from your iCloud-hosted Match library - the new version will be a DRM-free 256kbps AAC file. For further information about this process, contact Apple.
If you upgrade your music to the DRM-free version you'll need to update your Music Index using the Sonos Desktop or handheld Controller before the changes will be registered by the Sonos Wireless HiFi System.

Hello Sherburn, Apple m4p tracks are DRM (Fairplay) protected and Sonos will not be able to index nor play them. There is a way to turn them into DRM free tracks with a iTunes Match subscription as described here: click me Regards, Daniel H.
and why would I allow Apple to fleece me again when I already paid for the music.

I realize this is an old thread but the DRM issue should only be a problem if you want to use the Sonos application to play your music. I have little desire to use their app. I just want to play my music directly from iTunes on my Mac or iPad to the speaker. I just want to have the Sonos software act as a virtual sound card that redirects the digital audio data that the sound card circuitry in the Mac and iPad converts to analog and instead redirect it to the Sonos speaker over the WiFi.

When you download an Apple Music track to your iPhone, Windows computer or Mac, it's got DRM. You'd better download a converter like TuneFab Apple Music Converter to convert iTunes songs to MP3.