I see at least 2 problems
self.currentUserProcess1 = Label(self.frameP1, text="Current User p1", font=("Helvetica", 10, "bold")) self.currentUserProcess2 = Label(self.frameP2, text="Current User p2", font=("Helvetica", 10, "bold")) p1 = mp.Process(target = process1, args=(gui.currentUserProcess2,)) p2 = mp.Process(target = process2, args=(gui.currentUserProcess2,)) === def process1():