>Compare the back of one card against the other. Also compare >the 'down edge' of each. A good bet is that something >separated on the 16, still allows the 16 to insert fully >because it mates, but does not allow anything else to insert >fully. And no the side lock on the card is not involved.
That's exactly what happened. A tiny piece of the card came out in the slot--it's not even visible from the outside. Now how do I get it out? Guess I have to find a repair center.