This question already has an answer here:
Just what the subject said.
Wife just got a new iPhone 5c iOS 7. I had pulled all the goodies off her old android (now my new android) and wanted to dump the pics and stuff back onto her new phone. Alas, no joy.
iphone prompts 'Trust this Compter?' I select to trust, and it just pops back up again, looping endlessly.