Every once and a while I get a file that has blocks that can't be exploded.  The author un-checked the Allow exploding checkbox when the blocks were created.  This week I'll explain how to get around the problem by using the REFEDIT command.

To start with, you need to find the base point of the problem block.  Left-click on the block that can't be exploded and look for the blue grip.  Remember where this point is and the layer the block resides on because you will use it to redefine the block definition later. 

Now, double-click on the block instance or start the REFEDIT command and select the block.  Make sure you are in the top level of the hierarchy and pick the OK button. Make a copy of all the elements within the block and move them away from the originals..  Pick the remove from working set button, select the copied entities, and finish the copy command with an ENTER.  Exit the REFEDIT command by using the Save Reference Edits button..

Set your layer to the same one as the original block instance and start the block command.  Pick the same block name from the drop down list, match the base point to the original blue grip point, select the copied objects that were removed from the REFEDIT command, make sure the Allow exploding check box is checked, and pick the OK button.  Pick the Yes button in the dialogue box reminding you that all instances will be updated.

All the blocks that could not be exploded before have been redefined and can now be exploded.