I don't understand how the utf-8-bmp codec will help to fix the tkinter. To fix the tkinter, you need to fix the Tcl/Tk, but it is outside of Python. While Tcl does not support non-bmp characters, correct and non-ambiguous working with non-bmp characters is not possible. You should choose the method of encoding of non-bmp characters and these methods will be different for different applications.