I have set the modelspace background color to 9 and then using the following find the integer value used by preferences. (setq prefDisplay (vla-get-Display (vla-get-Preferences (vlax-get-acad-object))) color (vlax-variant-value (vlax-variant-change-type (vla-get-GraphicsWinModelBackgrndColor prefDisplay) vlax-vbLong)) ) The color value is 46186688. When I attempt to put this value in the preferences I get the following error. :ERROR-BREAK.42 "Automation Error. Error setting preference property" [6.39] (intelligent-invoke #<VLA-OBJECT IAcadPreferencesDisplay 07f8c85c> "GraphicsWinModelBackgrndColor" 4 #<variant 3 46186688>) How can I set this value?