Had that dreaded "usb device not recognized" with daughter's ipod touch a couple of days ago.
I did all the googling and experimentation that retirement allows. (Too much time on pc in retirement)
It was not the usb as I tried another touch and a samsung phone thru that usb socket, and both worked..
Ferking thing still would not recognise it. So I plugged it in at about 5.00 pm and left it in, and left both ipod and pc turned on overnight.
By 10.00am, the next day, whatever was wrong had put itself right.
Whilst I would put in my claim for superior pc skills, it would not be true in the slightest. I have no idea what resolved it.