There are a few posts on this with varying views on what causes it what what the solution is.
The problem is caused by having your iPhone set to automatically download purchased music content to this device when made on other devices. If you look at Settings>Store on your iphone, you will probably find that the "Music" option is switched to 'On".
You can turn this off and the problem will no longer occur, but it will not fix the existing duplicates on the iphone.
If you do turn it off, then music will not automatically download to that device when purchased on another device. It will have to get to that device via a sync. I prefer to leave it switched on as I like the feature.
How to fix the existing duplicates on your iPhone:
- Select the Music option from your iPhone
- Delete all of the duplicated songs off the iPhone. To do this, either:
- (if it is separate songs that are deleted and you want to delete them one by one) select the Songs option from the bottom of the screen; individually select the song to delete by swiping left across the song; a "delete" option should appear; tap "delete"; the song should disappear, or
- (if it is an entire album that is deleted) select the Albums option from the bottom of the screen; select the album to delete by swiping left across the album; a "delete" option should appear; tap "delete"; the album should disappear
- At this point the songs have been deleted from your iphone: both the "original" and "duplicate" versions.
- sync the iPhone with iTunes, ensuring that the appropriate setting are in place to sync music from iTunes to the iPhone
- the sync should put the songs back onto your iPhone, once only.
- Check the music library on the iPhone and the songs/albums should have re-appeared but now they are there once only
- Problem solved.
However, a problem with this that I cannot solve is that this will need to be repeated every time an album is purchased from iTunes (which is messy).
- I could turn off the automatic download feature on the iPhone, but I like this feature.
- Alternatively, I could alter the settings for music sync-ing in iTunes that will mean that music never syncs from iTunes to my iPhone and will rely solely on the automatic download feature - however, there are times when I import a CD into iTunes and want it on my iPhone: This requires a sync of the music.
Does anyone have any thoughts on what a permanent solution for this is?