After install ZWCAD, the Grid display is turned on by default, so every time open ZWCAD, the Grid will display. 


Grid display is associated with the drawing, which means in the current drawing, turn off Grid display and save it, then open it again, the Grid display will not display anymore. 


So to turn off Grid display by default, you can save as the template file by setting the Grid display off, and then go to Options and select the new template file as the template file by default when ZWCAD opened.