When AutoCAD does an AUTOSAVE, it saves the drawing at the OS Temp folder with the name "DrawingName_Numbers.sv$", as specified on the OPTIONS dialog, and it sends a kSaveMsg message to all applications.
However, this kSaveMsg message may trigger some custom action on applications that are listening to this notification/event, but in the case of an AUTOSAVE, this is not the correct thing to do.
Because an AUTOSAVE does not trigger a CommandWillStart() notification, if we set a global flag from the CommandWillStart() notification tracking commands with “SAVE” on the command name, then we can detect if is an AUTOSAVE or a normal save called by the user.