Hi, this is a tricky level, in order for butterflies to drop you must remove all the virus. The butterfly only drops one at a time, so you need to make it fry as quick as possible. GOOD LUCK.
Samething happened to me too, I passed this level by using right side butterfly to pick up the last one, but to do so you need to have extra moves. Good luck.
Hi @Lynette merry Christmas, thanks for the tips . The first method didn't work for me, the last one still won't drop, but the second method work fine, and I passed.