Volvo clacking noise

My trusted Volvo mechanic can’t figure this out. Shortly after starting my car, there is a clacking noise that seems to be coming from an area near the glove compartment. It lasts for several minutes and then stops. There doesn’t seem to be anything wrong with the car. I’ve had it serviced, but can’t figure out what causes this noise. Any ideas?

Could be one of the actuator motors for the AC system

As db4690 above says, it does sound like a problem with the ventilation door actuators. You could try messing around with the AC and Heating knobs, see if anything you do makes it worse or better. That could provide a clue a least. It varies from car to car and year to year. Some of these vent door actuators are vacuum controlled, and some are little electric motors, usually stepper motors. One of them could be stuck or failing.