Since you have to rebuild your scene anyway, you might want to try this: First build the center figure with props, cloths, etc. Set all the lights, and save the lights, then the .pz3. Render it in Firefly with your chosen options to make sure the smaller scene works by itself. Then create a new scene, and build the second figure with everything. Save it under a different name. Continue until all figures are done, as seperate scenes. Now create a new scene with the default lights. Import the first scene and render. If it renders, then import the remaining parts one at a time and render. If everything renders correctly at this point, it looks like it's the lights. If it fails at any point, you know you've got a problem with the number of materials and complexity of the scene, or that P5 isn't releasing all the memory back to the system after a render. Finally, when you reach the point where it breaks, reboot the machine, and load everything that caused the problem without doing any renders. Try rendering again. If it renders, the problem points to a memory leak in P5 and it's definitly a P5 bug. Very controlled testing can help pinpoint the problem. I'm working on building a scene to send to Stefan at CL because of just this kind of lockup. My problem right now is I delete all my pz3 files at the end of a project, so now I have to recreate the problem and life is very hectic around here. Hard to concentrate on a real project.