Mushroom popcorn will pop in a microwave - all popcorn will. However, Mushroom Popcorn is very temperature sensitive and requires a higher temperature in order to pop into the ball shapes it is known for. At lower temps it will pop into mostly butterfly shapes. A microwave cannot provide the proper environment for it to pop at it's best.
So, if you want the Mushroom Popcorn to pop into it's characteristic globes, then you don't want to pop it in the microwave. If you don't mind it popping into the traditional butterfly shape instead, then the microwave is OK.
We recommend popping Mushroom Popcorn on the stove using a Whirley Pop Popper or Stainless Steel Popper. If you don't want to pop with oil you can use a Hot Air Popper (which is the fastest and easiest method).
Mushroom Popcorn is typically used for making Caramel Corn, Kettle Corn, or some other type of "candied" popcorn. If you want a good snacking popcorn to make in the microwave, I would recommend you try our Movie Theater Popcorn, Tender Pop Hulless, or Itsy Bitsy Tiny Kernel popcorn. They are all delicious and pop well in a microwave popcorn popper.
Please note that when popping any variety of popcorn in a microwave you will find more un-popped or half popped kernels than if you popped on the stove top or in a hot air popper.