A “.dwg” file extension indicates that the file is an AutoCad Drawing file. The “.bak” file extension indicates the file is a backup file. When you back up a “.dwg” file in AutoCad, the program applies the “.bak” file extension, but does not make any additional changes to the file itself. To change a “.bak” file to a “.dwg” file, rename the file extension in Windows Explorer. Writer Bio
