There are a few reasons why some of your tracks may have not synced:
- Local files (e.g. MP3s) from your personal hard drive can't be synced to Mighty. Mighty can only sync tracks from Spotify or Amazon Music. - Spotify and Amazon Music have placed content restrictions on the tracks and they are not eligible to be taken offline. The restrictions can be put into place for in specific countries or globally. - Some Spotify playlists (e.g. Rap Caviar) now include video content which can't be synced to Mighty.
If a playlist contains tracks that can't be synced, Mighty will skip those tracks and the tracks that are eligible will be synced.