I have a Bernina[used] that I purchased a year ago, and the first time I cleaned the bobbin area, I had this problem, and after playing with it a few minutes, realized that the snap on the left that held it in place, wasn't totally snapped. So, now I know that I have to push it in with a little more effort, and listen for the second click. This may not be your problem, but that was what happened to me. Good luck with solving the problem.