I have been spending a lot of time creating playlists on a macbook to get settled into a new device. The file types consist of m4a, mp3, and FLAC. I have all files organized in folders by Artist. Some artist folders/tracks aren't being copied over, and I'm getting errors on the macbook while using Android File Transfer (AFT) saying some files can't be copied, that folders can't be created, and that the device isn't connected when it clearly is and I can still interact with AFT, although i get spinning pinwheels after an attempt at importing. Please advise.