Whenever I open a drawing (on top of a existing drawing) in Auto CAD 2010, I get a dialog box asking me to save the existing drawing. It is like this only for the past few days.. I set SDI to 1, Filedia to 1. Still not working, SDI variable is obsolete says ACAD Help.. I've been fooling around with my Command line customization lisp, has this led to this error. I always have 5-6 drawings open at a time and use Ctrl+Tab to access them. What should I do?