I received a very complex drawing from a building contractor (29 mb - over 600 layers). I need to extract some layers and copy it to another(blank) dwg. So far I managed to reduce the size to about 6mb by exploding, deleting unwanted parts and purging. The number of layers is reduced to 83. At this stage I am hitting a wall: whenever I select a line with the mouse the whole dwg is highlighted. When I explode further, part of the drawing is deleted exactly the part I need. I tried group: can only find numerous unnamed groups - too many to explode one by one. Also when i doe that the unnamed groups do not go away after exploding them. They keep on coming back. I tried to copy the dwg to a new dwg but nothing is inserted in the new dwg. Anybody has an idea of what is going on here?