Q: iPod Classic (older). vs Windows 10

Does the device otherwise appear to work normally, e.g. with headphones?

You may have fluff or debris in the docking port preventing a proper connection. You can look for this and, if found, tease out gently with a thin sliver of card or plastic. Otherwise try a new cable. See also If iTunes doesn't recognize your iPhone, iPad, or iPod - Apple Support.

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