Hi ...I hope i'm posting in the right place .In AutoCAD 2013 , If you are using black background for your drawing , DWG thumbnail in windows has the same color .is there anyway to background for thumbnail be white as previous releases of AutoCAD ?!

Sure, but you'll have to change the background color in Model space with Options to get it.  You won't get one without the other.Dave.

Thanks for your answer ...But i mean without changing color of working space like older versions ... which seems impossible now .