I have AutoCAD 2013 and I imported a revit drawing to autocad and I need to change some 500 blocks and all blocks just need to change the layer to "0". So I am doing them now one at a time "Help" Brent

select everything. ("select" "all")Open the properties manager. One way is type "mo".In the top line showing selection, change it to just "block reference"In the layer property, select "0" Other ways to select all blocks, then use the "chprop" command.  

maybe I did not make my self clear. Within the block editor I select all the object and select "0" layer. The way you are having me to that is only change the object to a curtain layer. Does that help you Brent

Well yes that does help me read your mind better. :)Lots of lisp routines out there to do this.Maybe one at this site:http://www.draftsperson.net/index.php?title=FixBlock_-_Free_LISP

Perfect thanks