Mine does too. It hasn't always rattled - has only done it since last summer. I mentioned it to the dealer when my car was last in for a service, took the technician out on a road test so he could hear it for himself and was told when I picked the car up it had been fixed. It hadn't

I've not done anything about it since as it has been winter and I've not needed to use the sunroof so it hasn't bothered me, but now it's warmer I'm using it again, so it will be brought up again at the next service.
Another problem I have with it is when it is slid all the way back there it a rumbling - as if the wind deflector isn't working. If you put your hand up out of the roof slightly it stops. I also demonstrated this at the same time as the other problem and this wasn't fixed either
