My devices don't appear anymore on iTunes when I connect them
I have version 11.1.3.8 of iTunes.
Since I installed it, when I connect the devices to iTunes (iPod, iPad, iPhones), they are not visible anymore in iTunes.
I can see they are connected to the computer (I can access them) but why don't they appear in iTunes.
Finally, if I try to go to Files / devices / synchronise, "synchronise" is not accessible.
Can you help me ?
Thank you
iPod touch (4th generation)