If you have an iPod shuffle, you'll need to enable disk use in iTunes instead.
Note: Make sure you have the latest version of iTunes installed before trying these steps.
How to apply the "Manually manage music" option
- Open iTunes.
- Connect your iPod to your computer.
- Select the Device button near the top-left corner of iTunes.
On the "Summary" screen, check the Manually manage music and videos box (under "Options").
- Click Apply.
Note: If you disable the "Manually manage music" setting and then sync your device with iTunes, you may lose any items you've manually transferred.