instal the last version for ipod Old Snook

Short of a clean Windows 10 install I don't know what else to do. reinstall Apple Mobile Device Support driver (usbaapl64.inf) - same behaviour.uninstall iTunes, reboot, reinstall iTunes, reboot - same behaviour.different USB port on the same computer - all behave identically.different computer - tried it on another Windows 10 machine with an identical version of iTunes (12.7.4.76) - works flawlessly (with the same sync cable).

iTunes doesn't detect the device at all, but once the connect/reconnect loop gives up the iPod appears as a mass storage device - but iTunes continues to ignore it. The iPod appeared to connect, then disconnect and reconnect again in a loop until eventually Windows gave up and said the device had malfunctioned. However, I plugged in this newly purchased iPod to the family PC (via USB) and strange things began to happen. By this I understand that syncing has worked on their family PC (running Windows 10) in the past, but updates may have been run / fiddling may have taken place since the last successful sync. One of the parents already has an identical model which was 'working fine' (although hadn't been synced for over a year). I have a used iPod Classic 5th Generation (A1136) that was purchased for a parent as it is compatible with all their 40-pin gear.

Instal the last version for ipod Old Snook