I have a model I created and animated using Maya. When I import the model into the scene and click on the model’s mesh, I get the error “Preview scene could not be loaded”. I’ve added multiple models before this one and I’ve not received any errors.
I just had this same issue crop up when going through my animator and lengthening the transition times on the animation transitions. this error came up and it stopped displaying the little chart where you can grab the sliders and change transition times. the only thing i could think was that something in the unity animator was loading and storing those little graphs (calling them previews), and never unloaded them, then got to be too many loaded at once.
I closed unity and reopened and then it worked fine, i guess that cleared the loaded previews.
Not sure about root cause though, i assumed it was something on unity’s side