I want to download playlists and albums to listen offline during my vacation. I am downloading to a 16GB SD card. Every download is fine, I see a green symbol in the playlist or album. After I stop Spotify and start again, it appears that most downloaded playlists have no green symbol but gray. After re-activating Spotify, my Samsung Galaxy SII downloads the missing numbers to my internal memory, which has not enough space. When checking a playlist, I see that some songs from the playlist have been downloaded, others are not.I have Spotify Premium Family. I've removed the app and then reinstalled and then restarted the downloads. The problem remains.What should I do to get all songs downloaded on my SD card and to keep it there?