My particle system wont play

Well, we need much more informations. Did you made your particle system active on awake ? Loop ?

The same thing happened to me... now in 2022. I fixed it by creating a " public ParticleSystem particleExplode; " Then in the hierarchy I made it a child of the item to spawn on and dragged the PS from the hierarchy to the inspector. Previously I dragged the prefab PS to the inspector and it wouldn't play.