I just replaced my HDD and did a fresh install of Mav then restored everything from timemachine. now when i plug in my phone to update in itunes i get a window that says " this computer is no longer authorised" so i sign in with my apple id and it says "this computer is already authorised". close that window and we start again "this computer is no longer authorised" it's going to delete songs from my phone now. anyone else experiencing this? what do i do?