My iPod Classic 160 GB, late 2009, has stopped syncing library content (using iTunes ver 10.6.1). The iPod still has 135.8 GB free memory. I have many Audible books in the "Books" library, but only four of them are synced to the iPod. All podcasts, as well as iTunes U, sync OK. My DVDs and converted movies are also affected by this problem - out of 10 movies, only three are synced to the iPod.
Does anyone have any ideas or advice?