If IDLE stops responding when a menu opens a dialog on macOS 27, your Python script may not be responsible. The Python releases of 21 October 2026 include updated macOS installers for a documented Tk freeze. Check the distribution, the interpreter actually launched and the results of a controlled acceptance test, rather than trusting the version of an arbitrary python3 command. [1]
What is confirmed, and what is not
According to the release notes, the official macOS installers for Python 3.15.1, 3.14.9 and 3.13.17 include a prerelease Tk build containing the fix. This does not guarantee a fix in every Homebrew, Conda or other distribution. CPython issue 158053 documents menu actions as triggers; its 21 October update identifies the new installers. Not every IDLE crash therefore has the same cause. [1][2][3][4]
Prerequisites and recovery
This guide is for learners and administrators of small Python workstations running macOS 27 in a local graphical session. Back up project files and record the previous Python/Tk versions, distribution and launch method. Save open work before testing: force quitting can lose unsaved text. Keep a verified data backup; an old installation is not a substitute. Coordinate installations on managed machines with the administrator.
Five steps to isolate the problem safely
- Identify the interpreter first. In a new Terminal session, run the first diagnostic block. python3 is an example: substitute the deliberately selected interpreter path if several installations exist. Compare its path and version with the IDLE app previously launched from Finder. Review local user paths before sharing them.
- Test Tk separately using the second command with exactly the same interpreter. Python documents a demonstration window showing the Tk version. Record the result and close the window normally. A missing tkinter module differs from the documented menu freeze. A working demo does not yet prove IDLE menus work. [5]
- Choose the appropriate update route. For python.org installations, consult the release page for the existing series: 3.13.17, 3.14.9 or 3.15.1. Check the macOS package, signature/integrity information and prerequisites, then follow its installation instructions. Do not change major versions solely for this issue. For other distributions, follow their supported update process and explicitly check their bundled Tk. Never replace or delete Apple's /usr/bin/python3. [1][2][3][6]
- Run a focused acceptance test. Repeat the diagnostics and Tk demo with the updated selected interpreter. Launch IDLE with the third command so an old Finder shortcut cannot confuse the comparison. Use a new disposable file: open Settings, test Save As and run only the harmless example in the last block. After each dialog, check that both editor and shell remain responsive. [7]
- Release the workstation only after checking the normal Finder launch and a copy of a representative project. Record interpreter path, Python/Tk versions, launch method and outcome. Do not assume virtual environments or independently packaged applications are automatically repaired. If testing fails, stop production changes; use an existing editor if necessary, without reopening the problematic dialog with unsaved work.
python3 -c "import sys; print(sys.executable); print(sys.version)"python3 -m tkinterpython3 -m idlelibprint(2 + 2)If the problem remains
If tkinter is missing, consult the interpreter distributor; an arbitrary pip package named tkinter is not a replacement for its Tk integration. If only your application freezes, investigate its execution separately. A useful report includes macOS version, a sanitised interpreter path, Python/Tk versions, minimal menu steps and the result with an empty file. Do not publish private projects or complete system reports without reviewing them. Avoid framework symlinks, local Tk patches or disabling security as quick fixes.
Acceptance criteria and date
Acceptance requires a working Tk demo, responsive affected IDLE menus, successful saving and test output, with the normal launch using the same verified build. This does not guarantee every application works. Updated: 24 October 2026. Source-based instructions, not an independently performed macOS/IDLE reproduction test or buying recommendation. No affiliate links.