Hey @dan, I downloaded build of the day, and try it, It solves partially the problem, let me explain:
First I am able to load the material editor, add PBR without crashing, and it is very appreciable
Loading images into PBR folder works great, but, on Render mode only, the base color if loaded as image, appear in good into the icon panel, but appear in red (as red color) into the viewport.
It is only into Render mode, because in Raytraced mode it works well with the right appearance.
In render mode, all other maps, like Normal, or roughness affect well the render, in fact all object appear as “red base color” if a file is affected.
If I uncheck it, the base color define appear well and replace the red.
So to resume, affecting and image base color in Render mode only, appear in red color into the viewport.
Hope my describe could help you
Let me know, but thank you for help