IPhone will not sync music - Apple iPhone 3GS Black (16 GB)

Hey friend. What kind of files do you want to sync between iPhone and iPad? Let's say, if you're planning to sync music from iPhone to iPad, you can simply rely on iTunes.

Please note that if you have hundreds of thousands of songs in iTunes Music Library, you'd better create a separate playlist for the songs you want to transfer. Then you can choose the playlist when you sync music to iPad with iTunes. The following guidance will show you how to transfer songs from iPhone to iPad with iTunes.

1. Transfer Purchased songs from iPhone to iTunes Music Library.
Sync Music
2. Connect iPad to computer with USB cable.
3. Click the iPad icon and choose Music.
4. Check Sync Music, and choose the iPhone music playlist.
5. Click Sync at the right bottom.
3 Ways to Transfer Music from iPhone to iPad

All you need to do is go to your music library and under the edit button on the top tool bar select "select all" then click "copy".
Then go to your iPhone 5 music library under the "devices" section in ITUNES and click on the MUSIC folder, once your in this folder select "paste" under the edit menu. And your music will then start to transfer.
More sources: Sync iPhone 5 to iTunes music libary

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There are 2 ways,

1) sync music to your iphone through itunes by selecting the music tab on itunes and select the song you want to sync

2) sync by manually dragging your music to the iphone icon in itunes. you will need to click off the box "manually sync files to iphone" at the bottom of itunes

Connect your iPhone to iTunes and do the following:
1.On the summary tab of your iTunes sync settings check "Sync only checked songs and videos"
2.In your music library check all the songs you want to sync to your iPhone
3.Make sure there are no exclamation points next to any of the songs you want to sync to your iPhone
4.Make sure you have authorized your computer for all Apple IDs for purchased music you want to sync to your iPhone (in Store>Authorize This Computer)
5.Check "Sync Music" on the Music tab of your iTunes sync settings
6.Sync your iPhone
If above can't help you, the below article may give you a guide.
Transfer music from my iTunes library to iPhone
Good Luck!

Unlocking does not effect syncing make sure you have most recent itunes. make sure you don't manually mange music if you want phone to sync. when phone plugged in click on phone to see settings make sure sync music is checked

1. Open iTunes. Open the Edit menu on Windows or the iTunes menu on a Mac. Click the "Preferences" option. Make sure the "Disable automatic syncing for all iPhones" check box is selected.
2. Plug your iPhone into the computer and wait for iTunes to recognize it. Click on your iPhone's icon on the right side of the iTunes window. Click the "Music" tab.
3. Select the music you want to sync to your iPhone using playlists. You can also select the option to sync all your music to the iPhone.
4.Click "Sync" when you're done customizing your settings.
Get more details: Transfer music files from Mac to iPhone

1. Download iTunes.
2. Connect your iPhone to the computer.
3. On iTunes, you should see your iPhone listed under Devices.
4. Click on your iPhone.
5. Go to the Music, Applications, TV Shows, and all those other tabs and set your preferences.
6. Click Sync.
Now you can send music from iTunes to iPhone.

This is easy:

On the summary page of your iphone on itune there are three options in the bottom third of the screen just above your capacity summary.

Make sure the button "Manually manage music and videos" is checked and you can drag and drop.