This only happens in P6 this way. And it seems to be a random thing...you can resave a file 30 times without it happenning. In P5, it required an ugly blackout reboot crash to trash a scene like this. Saving to different names: it trashes the file you renamed it from as well as the new named file. Then as you reopen the older named files, it trashes each one (one by one) backwards. I've gone through 6 like this. I shut off the .pmd file option and reduced these considerably though, could just be a coincidence. "Is it because you have Meshes turned on in the view?"...no. These were in either full preview (skree3D) or document style. They either come back as dead wireframe (above) or even worse...multicolored forms with no wireframe at all... " I've noticed, that you get these corrupted pz3 files when having lots of unconnected nodes in the material room"...should not be an issue as P5 handled this fine. I usually have a lot of connected nodes as I use shaders on everything.