iMac 10.11.6, iTunes 188.8.131.52 Regular update of iOS on iPod Touch, everything proceeds normally until the very end, when I get the message to leave the iPod attached as it restarts. A few moments later, during the restart, I get a msg in iTunes "iTunes could not connect to the iPod touch 'ABCD' because an invalid response was received from the device."
At this point, I disconnect the iPod, let it finish restarting, and reattach it. iTunes recognizes the device and everything is back to normal.
This has happened for the last two iOS update cycles, on two different iPods. The error msg does not interfere in any way with the update or the subsequent use of the iPod, but I am curious why I am getting this message. I have tried different cables and different ports.