I have a scene which takes 12 seconds plus to enter Play Mode as Unity saves the scene every time I enter play mode, I can understand if I had made some changes to a component etc but if I enter play, then stop and then hit play again it takes another 12 seconds as it saves the scene again. Why does it save the scene if no component is dirty and nothing has changed?
How complicated is your scene?
Are you using any Asset Store assets? Some of them have hooks that run when you play the game, which can add time.
Its a simple scene of a few objects that are high poly counts but a basic scene. I profiled the startup and the time is only being spent saving the scene, but I just dont understand why it saves the scene everytime. Surely Unity knows that nothing has changed and it does not need to save the scene.
It saves the open scene because in play mode you’re modifying the open scene, and Unity wants to return to the open scene exactly how it was when you hit play as soon as you eventually exit play mode. Unity probably isn’t built smart enough to differentiate between modified and unmodified scenes when it does this, likely due to the can of worms that would introduce regarding having multiple scenes open at the same time (some modified and some not).
Is your project on a fast SSD?