I have an Echo Plus 2nd generation and an Echo Link. The Plus and Link are in the same group. For background but probably irrelevant I am also using an Echo Connect and several plugs. The Echo Plus accesses my iTunes library running on a Windows 10 PC through My Media just fine. I have set the prefe...

FWIW My iTunes library has 12,467 items and although I have not exhaustively tested it, My Media seems to be having no trouble handling it. When it did the index, it actually found some more items (13,032).