Yes, has happened to me, too. As Bill pointed out, once it happens it very well may happen again. I caused the problem the first time when I tried to adjust it beyond it's limit. It was when I first began using the lift in the table. Idiot that I am, I only looked at the bit height above the table and never looked to see if I was turning the adjustment knob too far. After doing the same thing a second time, I'm a slow learner, I now pay attention to were I am along the screw. Hasn't happened since.