Thanks for your input, Sarah.
I had the same issue - a model rendering fine one day to no render output the next and the “Finished Loading Plugin” message - and using your info did the following to resolve it:
Turn on ‘Material Override’ and run a render
If a render is successful, review what new components have been added to the model since last successful render with materials on.
I had added a number of kitchen and bathroom components since previously trying a successful materials render and assumed a material in one of these groups was causing the issue.
Right-click on the group/component and select ‘V-Ray UV Tools’, on drop-down select ‘Remove Materials’.
Then go to V-Ray Asset Editor - Materials List and Purge the list. THIS IS IMPORTANT BECAUSE THIS IS WHERE THE PROBLEM LIES. If you know the materials you have added since the problem occurred, you can just delete these from the list but you will then need to add new materials which work in V-Ray.
Following this, the render output was fine.
So the issue seems to be in the materials applied to imported components from 3D Warehouse or old models from my own work (before I started using V-Ray). Unless they have been developed for V-Ray rendering it is a good idea to remove the materials (check face orientation) and apply new materials.
Thanks again