This was me. I have a MR that we used for several months without a single issue. The button the buckle has to be pushed in at the top, but it wasn't anymore physically difficult than any other seat. Then one day, the buckle wouldn't depress. I also couldn't slide my daughter out of the harness loosened all the way because she couldn't contort her legs enough and the harness was on the middle loops for the slot she was on, so I had to entirely unthread the seat She is now up a slot and on the longer harness loops, and it has stuck two times since then. I hate to think of not being able to unbuckle her in an emergency, but I have to use the MR. Every time I call Graco, they tell me they are out of replacement buckles and I have to continue to wait. As soon as I can afford to replace the seat, I will.