A feature that AutoCAD now has is the ability to lock blocks from editing. A seemingly nice feature but what if you really really need to edit the block. Well, they hid the key under the mat. Where is the mat you ask. Why of course, it is in the same place you open the door. The BLOCK command. To unlock your "door", select the block command and select the block you are interested in, now look at the dialog and notice the CheckBox to "Allow Exploding", what are you waiting for, check it. Now the door is open. AutoCAD will make sure you want to unlock the door by having you confirm the operation. Come on in and make yourself at home.