How do I change the Environment for Asset Previews? The only way I found so far, is to select eg the material and check ‘Use World’ for preview. The standard previews are very dark.
What do you mean by very dark? Can you please show screenshot with an example? Previews look fairly normal to me 
Hmm that’s really weird, could send a simple empty scene with just a material where this is happening?
Sure. Scene attached. This happens in every scene, every material here.
Sample Scene.blend.zip (201.4 KB)
Yes, sadly that’s what I suspected. This is caused by the color corrections in the scene. During viewport rendering we reset the blender color management settings to default(but after the viewport render is done we revert them to their old values). We do this because don’t yet support Blender color corrections and it has been on our roadmap for a while. Note that the panel is also hidden when V-Ray is active. Also with these settings the previews in Cycles should also look darker.
Ah ok. If it is hidden, how to I change the Values? Change back to Cycles adjust and back to VRay? These are my default values when using Cycles, but I wasn’t aware that the influence VRay because, as you wrote, they are hidden.
Yes, you would need to change to cycles to change them. We will try and add full support for them at some point.
Thank you for the quick solution!