Have you tried typing SCL at the Command: prompt? What happens then?
What version of AutoCAD Architecture are you using? Do you have any third-party add-ons installed? "SCL" is not a command for me in AutoCAD Architecture 2014, and I do not recall it being one in previous versions. Perhaps you have some third-party add-on installed that has its own method of setting/saving a drawing scale. This was quite common before AutoCAD Architecture and then AutoCAD itself added a drawing scale; we used to use the USERR3 system variable to set/save a drawing scale factor for use in our custom LISP routines, although we did not have a reactor program that would prompt you to set a scale if you opened a drawing in which USERR3 was set to 0.
David Koch
AutoCAD Architecture and Revit User
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