I recently had my 4th generation 16gb nano stolen>It had 4050 songs on it.
I bought another nano exactly the same size, Restored it , ticked sync my music only, and ticked convert to 128 kbps
Result it only synced 3850 songs
I restored again checked everything but again only 3850.
Audio bar in iTunes is showing I still have 900 mb spare capacity but Ipod is showing full
Retrieving data ...