I have identical copies of my music files on an external HD and a NAS (QNAP) (around 2,000 albums). If I import music from the external HD, everything is fine. But for some reason the library importer does not import 275 tracks (out of around 60,000) from the NAS. The failed imports seems to be random, i.e. some albums, some tracks, so no particular subfolder or something like that. The files exist on the NAS and play fine with other player software. JRiver does not state a rationale for the failed import.