Hello AllI have a Library with blocks which I made and since we are doing work for a big client, we have to comply with his CAD standards such as Layer names and colours.My question is :is there a way to make these changes in one go or do I have to open each block and do the changes the old fashion way?Rog

I don't think you can make wholesale changes.  Maybe the best you could do is write a script and let it do the drudge work.

A script. Although I use AutoCad since version 2.16 I never realy got into the deep end of it I can do some lisp program but not much more mate.I discovered just recently how to record a macro, would that do the trick?Will trythanksRog

A script might be a set of instructions that open a drawing, make changes to a layer name and color, purge, audit (check for errors), do a zoom > extents then a save.  It would cycle through a folder or directory of drawings doing this to each and every drawing.Check out AutoDesk's free ScriptPro at their website.

Will do that and post the result.Thanks very much.