How to unlock sharp stove?
Not super familiar with Sharp Microwave ovens Convection or not,
but most microwave ovens can run into at least two reasons that they won't open and both require you to remove the cover over the whole oven - If the door has a push-button to release the door, you could find inside it has popped free of it's pivots and is not lifting up the latches on the door so you can open it, or is has actually snapped that latch. The other thing I have seen more on Panasonic microwave ovens and again moreso on the newer Inverter ovens, is that the latching assembly inside is attached to too thin a piece of metal and the metal actually bends - now your door and it's latching assembly and switches don't line up properly.
In that case you will still need to remove the cover and do your best to realign the switch assembly with the front of the microwave so that the door can click in and out easily.