- There is no available space on the iPod hard disk when it is used as an external FireWire or USB hard drive, yet the disk looks like it is empty or only has a few files on it.
- iTunes cannot copy any songs to iPod even though it says the music library is less then the iPod drive capacity.
When disk use is enabled, the space on iPod is shared between the files you store on it when it is used as a hard drive, and the songs and videos that iTunes saves on it. If you fill the iPod with songs in iTunes, you won't be able to save any files on it in the Finder (Mac OS) or Windows Explorer (Microsoft Windows). If you fill the drive with files in the Finder or Windows Explorer, you won't be able to save any songs to it in iTunes.
To make room for files on iPod when used as a hard drive, delete some songs from iPod's music library in iTunes.
To make room for more songs in the iPod music library, delete files stored on the drive using the Finder or Windows Explorer.
Important: If you copy a music file to iPod using the Finder or Windows Explorer, iPod cannot play it. You must copy the song to iPod using iTunes if you wish to play it.
If iTunes or Windows Explorer report an incorrect amount of space, see this article.
See this article for information on how much content will fit on your iPod.