Volkswagen is aware of this defect and has extended the warranty on many of its cars to 7 years (for example, TSB #0603).
Volkswagen Is Aware of Window Clip Defect
You can call pretty much any authorized VW service shop and they’ll tell you this is a common issue. Here’s an official service report sent in by a user:
“Removed the right front door panel and window, found the window has fallen out of the window clamps, technical bulletin 64-08-06 covers this problem … removed rubber insulators from the window clamps and scuffed them with 120 grit sandpaper to remove glossy finish, applied adhesive to the rubber insulators and reinstalled them. installed window and torqued the clamps to 11nm, installed door panel.”
There are even reports of this happening multiple times to the same window. Placing the window back on the faulty clamp is not enough. Make sure to ask your service station if they are going to use an adhesive - hell, even duct tape would be better than nothing.
Who’s Having the Most Problems?
Window regulator complaints span multiple VW models, but seem to be a particular sore spot in the 4th and 5th generation Jetta.