Instead of a straight sync w/ everything, set up iTunes to manage your music manually.
I'm trying to sync custom ringtones to my iphone 5S and it just doesn't work. I'd like to know how to do 2 things:
1. How do I clear the list of ringtones? I have so many duplicates and I can't keep track of them all. I want to delete the dupes from the itunes list.
2. Why don't most of my ringtones sync? This is the most frustrating part; usually around 20-30% of my ringtones will sync, but then I'll add a new one and sync it.....and then half of them disappear from my phone or maybe a few more show up. It doesn't matter if I sync it multiple times, only if I add new tones or remove tones.
I am a first-time Apple user (since ~1993) and I'm seriously considering selling this phone and going back to Android forever. Thanks for any help on this.

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