my break makes a squeaking noise. on 2005 BMW X5

my break makes a squeaking noise, change break pad about 4 months a go. What is the problem, could it be the rotter?

Asked by for the 2005 BMW X5
bmw reccomends replacing pads, rotors and sensors when replacing brakes. just replacing the pads will not renew 100% braking.
reccomend using bmw parts for this job to make it right.

1 more answer
It could be the rotors. It could be the pads wearing not quite right on the old rotors.
There should be no noise. Check the pads for wear. Sometimes we will see the shims come loose on the back of the pads. These will start moving inside of the calipers and make noise under braking. Also with BMW brand does matter on what you put on for brake parts. Most BMW will use Zimmerman rotors, front and rear, Jurid pads on the front and jurid pads on the rear. These are what come on BMW brand new.