Your error was caused by the memory leak causing havoc with the undo buffer. You can cause a crash easily by using the copy, paste, or replicate/duplicate commands on imported meshes, or high poly native meshes such as trees. I have seen this myself. anytime you are making replications/duplications of imported models or high poly trees save the file often and restart Bryce. Make sure you rename the file each time as you do not want to copy over a good save with a corrupted one. Restart Bryce because that is the only way to clear the clutter from the undo buffer. Do not save as you close the file, save first then close. Because you need to check the integrity of the save and make sure it did not go corrupt and balloon to 1.98gb, another variation of the same memory problem issue. Remember that Bryce 6 compresses files in a way that bryce 5.5 did not, so you need to know the difference between the file size on disc and the size in the page file history. Also, try to never use the undo command. it too gums up the memory and can lead to crashes. Also, I have found that Bryce is sensitive to any and all system instability at the time of a save. I have found that the mere act of minimizing Bryce to work in other priograms then restoring Bryce causes the undo buffer to go crazy. So try not to work in other apps while working on scenes with alot of replications or duplications, and especially when saving files in Bryce. the truly deadly combination is perforiming lots of replication commands and undo commands while jumping between Bryce and photoshop editing textures ot 3dsMax editing meshes. Hope this makes sense. The memory leak sucks.