Memory leak when using threads and tkinter
(As far as I know Tkinter is NOT threadsafe. This may cause this problem. So using threads with Tkinter isn't a great idea. I'm not even sure that you really need multithreading for this.)
Edit: Seems like you are just killing your childthread with this, the mainthread is still running.
But to solve your problem, one way is to force-"kill" the whole processtree. All you need is your script pid and a subprocess function. Try this code in your killGUI:
def killGUI(self): try: subprocess.call(['taskkill', '/F', '/T', '/PID', str(os.getpid())]) print("Process killed: %s " % str(os.getpid())) except Exception as ex: print(ex)This will kill your thread for sure.