All of a sudden both my Macs will not talk with either my iPhone or my iPad. When I plug them in, it asks if I want to trust this computer. I say yes of course. I have used both devices with both computers for many months without a hitch.

The device icon in iTunes is not present.

All I want to do is back them up and copy some podcasts onto the device. Obviously something changed, but I haven't installed any new software on any of the four between now and the last time I was able to access them.

I have restarted both devices and both computers.

Any suggestions much appreciated.