I am having the exact same problem with my brand new iPod Classic 160 on a rather new Toshiba running on Windows XP. It synced right for a few days. Since a few days, every time I try to synch I get the message "The iPod cannot be synced. The required disk cannot be found.", although the iPod is shown in the left pane of iTunes. The iPod is not shown in the explorer.
Meanwhile I have undertaken various attempts to get it functioning again (losing the contents of the iPod in the process):
- I have tried the various USB ports, with an with and without other USB gear attached to the laptop.
- I restarted the laptop.
- Next step: reset the iPod.
- I changed the registry settings as shown in
http://docs.info.apple.com/article.html?artnum=304996.
- I have re-installed iTunes 7.5.
- I have re-installed the iPod software.
- Finally I restored the iPod.
Nothing seemed to work. By now, I ran out of ideas how to solve the problem. Software problem in iTunes and/or iPod after all?? Any valuable suggestion to try other solutions?