Blank Python Idle Window When Opening Python File On Macos

For some reason, whenever I try to open a python script that has around ~450 lines of code, IDLE's windows simply appears empty and when I try to run it doesn't run anything either

Solution 1:

To learn how to run Python Python programs on a Mac, read Chapters 1 and 4 of Python Setup and Usage. Running from an IDLE editor is just one way.

IDLE uses the tkinter module which wraps the tcl/tk GUI framework. Did you read and follow the instructions of how to replace the buggy tcl/tk that Apple supplies? Read the entire page before starting! Ignoring this page is the most common reason people have problems with IDLE on the Mac. There are a few others, but I do not remember one that matches your description.