Importing a folder from my ntfs(readonly) part always stops after 26 songs. The
bar in in bottom right corner continues moving but no more songs are added to
the list. I can play the songs that have been added before it stopped ( always
the same 26 ). I have (not yet) tried removing some songs from the folder
because there are very much files (>600) and rhythmbox does not seem to read
them in a particular order.

I start rhythmbox with '-d' command line option so it gives lots output, but
after it has stopped loading in new songs it just says:

[0x9a40e30] [rb_playlist_manager_save_playlists] rb-playlist-manager.c:599
(09:00:58): saving the playlists
[0x9a40e30] [rb_playlist_manager_save_playlists] rb-playlist-manager.c:602
(09:00:58): no save needed, ignoring

from time to time.