How to Sync iPhone Ringtone on Mac?
A lot of iPhone users have problem syncing iPhone ringtones. Some questions are like "I can't sync ringtone to iPhone", "unable to sync ringtone to iPhone" and so on. Some are more detailed, such as:
"I have ringtones in ringtone folder yes have changed to m4r, can play ringtones on pc and all are under 30 seconds long, have tried syncing ringtones but can only manage to get one on my phone."
Well, if you ever encounter this kind of problems, the following methods will help you out.
Make sure that:
1. Ringtones play in iTunes
2. They show up under the ringtones tab
3.They are in the ringtone section of iTunes under library
If the ringtone is in iTunes and not appearing on your iPhone after a successful sync, make sure none of the song fields (song name, artist, composer, etc) have special characters (like quotes, for example iPhone-Ringtone the"-" will cause the syncing problem).
The Length of your ringtone. Although they show up in the ringtones in iTunes after a successful syncing , they will not appear in the custom ringtones section on your iPhone if they are longer than 40 seconds.
Ringtone Manager
For Mac users, if the problem still exists, you can use iPhone Ringtone Maker for Mac. It has a Ringtone Manager, which allows you to make and sync iphone ringtone skipping using iTunes.

Ringtone Manager has 2 lists. All the ringtone files in the left list are those saved in your iTunes, and those in right one are your iPhone ringtones.
1. Highlight any ringtone you need in any list, you can then transfer it between iTunes and iPhone. All the ringtones that are longer than 30 seconds can be synced freely.
2. You can delete or pre-listen to your iPhone ringtones in the right list to manage them.
So, all the sync or transfer iPhone Ringtone work can be done skipping using iTunes and your problem can be solved as well.
If you have problem making custom iPhone ringtones for your iPhone, check How to Make iPhone Ringtone on Mac.