BMW Repair: e 39 sunroof wont vent, complete travels, initialization procedure

Question
My sunroof opens front to back without any funny noise.  It rattles when in the closed position and it won't go into the vent mode...  Have you seen this?  

Answer
Kyle, haven't seen this in recent memory. Remove the side gaiter covers of the sunroof from the upper rear and check to make sure the glass retaining screws aren't loose. Adjust glass by screws and make sure the front edge of the glass is flush to 1mm below the roof line and the rear is flush to 1mm above the roof line. Tighten screws. Reinstall Gaiters. Try complete movement of sunroof. Close roof. Press 'vent' position. Press and hold 'vent' position until sunroof runs it's complete travels (about 30 seconds). This is the initialization procedure. Occationally Motor will loose this if encountered with debris or a misadjusted glass. If the motor still does not vent then you are looking at either a motor or more likely in your case (rattles you discribed) a mechanical failure of the sunroof cassette assembly ($$$). Not a bad idea to clean the tracks with the glass open and relube with a light high temp grease. These are just a few things you can do to try to remedy this to avoid shelling out the big bucks. Don't be suprised at a full days labor to install the complete cassette.
-Evan