martial, the issue is probably caused by a specific model. It's not intermittent, it's something in the materials of a specific model. If you load the scene that is blocking Reality and start removing one model at the time and then call Reality, you will be able to isolate the problem model. When you do, let me know what product it is and I'll see if I can find a solution.

Anyway, for learning purposes it's best to start with new scenes instead of loading old ones. I think that that is also the suggested strategy in the Reality User's Guide.

All the best.

Paolo

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