OK,
I've had this problem for a long time, but just with my shuffle second gen (my other ipods worked fine), but when I took it to the apple store, the tech there had no problem restoring it or autofilling it with his Mac. I've had it since Christmas, and have just now been able to get it to work. So I want to share what finally worked after reading many forums and posts....
I finally figured out that i needed to do two things:
First restore the Ipod. I could not do this with Itunes--kept getting a dreaded error, but after some digging I found that Apple released this utility in March specifically for this problem:
http://www.apple.com/support/downloads/ipodresetutility10forwindows.html
I downloaded and used it and it was able to reset my ipod shuffle quickly and easily--(yeah!), but i was still unable to write to disk during a sync (boo!).
Then I found that someone else was having the same problem with music that was using a USB hard drive that did not have a separate power source.
If there is too much of a power pull on your USB ports the Shuffle will not sync! This not only includes using a USB hard drive but a USB hub that is not powered independently. Which was so weird to me since both my Ipod Mini and Ipod photo had no problems syncing.
Fortunately, my USB hard drive does have an external power cord. I plugged it in, restored the Ipod shuffle again, and bam it now works! If you don't have a drive that gives you the option of an external AC adapter, using powered USB port to plug it into will also do the trick.
So look at what is also plugged into your USB ports. Unplug anything you don't need to sync and if you are using a USB hard drive or hub or anything that is not plugged into the wall, --plug it in!
Hope that helps!
Dell XPS Laptop Windows XP Pro