Newbie render problem, compositor gets image, image viewer renders then turns black


Newbie here, been working through Andrew Prices grass animation tut and i’m this close to getting it finished but something weird is going on. When I render to image the image in the compositor looks great but the image viewer initially renders the scene and then turns black. I’m sure it’s something to do with the scene/render layers but i’ve tried a ton of different combinations with no joy (at 2 and a half minutes to render an image that’s a lot of frustration), i’m at the end of my tether here.

Can someone throw me a bone here, it’d be greatly appreciated

p.s. the scene is on layer 1, the sun on layer 3 if that is of any help.

Sounds like something is going wrong at the compositing step. Do you have a composite node at the end of the node tree?

Ah, i had left it plugged into a viewer node in the compositor.

Cheers, i can gather together what remains of my sanity and hopefully get this finished over the weekend.

Muchos garcias