I have blender 2.93.5 installed as well as crowrender v0.31 installed and when i select crowdrender as the render engine, the shaders and lighting dissapear entiled and i do not have the material preview in the viewport, see image below:
but when i select solid mode in the vieport, i am able to have a basic view of the scene. See image below
When i select cycles as the default render engine again from the main render engine list, i get material preview and shaders + lighting back. see image below
so in conlcusion, i figured something is wrong with my setup or setting somewhere because if you watch this turorial from crowdrender adn 3:24 mark, you will realise that, teh shaders still appear when crowdrender in selected, however i am not able to determine what viewport mode is selected.
See image for 3:24 mark screenshot