This is has been explored in previous posts with no solutions or recent posts, so I will revive it.
I have an Xbox 360 with all update. I have a Windows 8.1 Pro desktop and a Windows 8.1 Pro laptop. Both are set to stream media to all devices on the local network. From each device, I can see and play the contents of the other devices libraries from Windows Media Player.
When I launch the system music player, it immediately finds the hosted libraries on both computers. When choosing a library, it tries to load one of the lists (Albums, Artists, Playlists, Songs, Genres) for a long time, until it states that it found none. Both computers have a library of >6,000 songs. When these computers had Windows 7 Ultimate, there was no trouble finding the contents of the libraries in the Xbox 360 system music player. One forum poster noted that he spoke with someone inside Microsoft who reported that Windows 8 was not completed at release and that it had problems broadcasting large libraries. The poster put a limit around 400 songs. I then emptied my library and began to add songs a few at a time. I was able to see and stream the contents of the libraries in the Xbox 360 system music player when the library was small. When the size of the library reached around 800 songs, some of the categories (Albums, Artists, etc.) could not find the contents. As the size of the library increased to over 1,000 songs, the remaining categories were unable to find the contents of the library.
So, this issue has been widely experienced by users for over a year. There has been a major update to Window 8 and a sizable update to Xbox 360, yet the issue persists and has gone unrecognized by MSFT, who continue to parrot nonsense lines about Xbox Music and Play To. Has any user found a solution to this or is MSFT finally willing to step up to the plate and work on the issue?