Hi Headhunter, Out of curosity after reading about deleting any element from a boolean difference, I did a cube booleaning a cylinder. Then I rendered to check. At the layer broswer, I deleted the cylinder in the difference and the result was that the cube remain and Vue was normal. I reverted back and this time move the cylinder out to the root. Again all is normal. Then I try removing the cube this time to the root with the cylinder still in the root, the system reported an operation error. So I am not having the problem (bug) you are experiencing. What do you think of all this? I'm using an intel with 384 Meg RAM running Win 98 (1st Edition). Bill