Doors closed, trans in park position, switch on ignition, wait till all fault messages have passed, milage reading should be displayed, hold the cluster button, a "!" symbol will flash and your due service will then be displayed, release button, hold button again until the words "reset" is displayed, release button and hold again, the service then has been reset, release button and press once to scroll to the next due item and repeat the process.
hope this helps
OOPS SORRY WRONG QUESTION ANSWERED.
Change the Climate Control MicroFilters.
They usually cause this.
Besides all sorts of germs can lurk in them so its good to change them regularly.
BMW recommend they get changed with every oil service ie. 15K in my 2007 BMW 525i E60.