SLVR USB Connection Disconnects

Hello,

I recently bought a new phone, the moto slvr, when i try to put on new songs it's a bit difficult.. The reason for that is:

I plug in my phone to my usb and then the the do not disconnect thing comes up on my phone.. then my itunes pops up and the cellphone thing pops up, not it seems like it frozen for a bit but it's just updating the phone. after if finishes updating i look at phone and the do not disconnect thing is now gone, i'm like okay whatever and then i try to transfer a song and it says that the phone cannot be read from or written too. I keep doing this over and over and no success, every once in a whlie i can transfer a song and this is a pain.

any ideas?

Thanks

anyone please?