I wanted to share this with other Bernina owners. My face is a little red, but if it happened to me, it could happen to you. Last night I was quilting furiously away on a wall hanging for my secretary, who is retiring January 4. All of a sudden, I couldn't get the presser foot to lower all the way. I was at my wit's end, and out of frustration, posted to the Yahoo Bernina Aurora forum, mostly just to whine.
When I checked back an hour later, there was a message from another forum member, who said she had the same problem and called her dealer, who calmly asked her, "Have you checked your knee lift?" Well, what had happened was, a book had slipped underneath it and was preventing it from releasing all the way. As soon as she moved the book, all was well.
On reading this I jumped up and went to my machine. Guess what? The end of the knee lift had gotten wedged against part of the inside of my cabinet! So, if you have any trouble with your presser foot - check the knee lift!