Microwaves are tricky, that's why we provide the Test Launch packet with each Discovery Kit!
Naturally, every kernel isn't going to pop. It's normal to have roughly 50 unpopped kernels and we take that into account when we fill our bags to make sure you still get a full serving of popcorn.
Try starting with a shorter time (around 2 minutes, 30 seconds), then add more time in 30-second increments, listening for popping to slow down to a couple seconds between pops before you stop the microwave.
Our kernels tend to pop better when they are at room temperature. They don't need to be refrigerated, but if you choose to store them in the fridge, make sure to bring them to room temperature before popping. We ship them with cold packs due to the heat of the transit trucks.
Some more tips are to make sure that your turntable is in place so that the popper is rotating and does not get caught on the sides and that there are no liquid spills in your microwave.
Another trick is setting the power level to 80% and adding more time. All microwaves are different, so this trick works at home, but doesn't seem to work in our test kitchen. You just have to play around with your microwave a little.
If you are still having popping issues, please contact customer service!