Upgrading Python on Windows doesn’t have to mean starting from scratch.
This post walks through a safe side-by-side upgrade, a full cleanup option, and provides a downloadable PowerShell kit you can drop into your toolbox.

Download the kit here:

Why use a migration script instead of in-place upgrade?

Windows installs of Python aren’t designed for true in-place upgrades. Different versions can break binary packages, scripts are tied to specific interpreters, and some apps bundle their own Python that you shouldn’t touch.

The safer pattern is:

  1. Install the new Python version side-by-side.
  2. Reinstall your packages into the new interpreter.
  3. Move or recreate any helper scripts / entry points you rely on.
  4. Update PATH and file associations.
  5. Uninstall the old version once everything checks out.

The migration kit automates most of steps 2–3 and gives you a repeatable process for future upgrades.

What’s in the Python Migration & Cleanup Kit?

The ZIP contains these files:

  • migrate-python.ps1 – one-stop helper that:
    • Exports packages from the old Python
    • Installs them into the new Python
    • Optionally copies your custom .py / .cmd scripts from the old Scripts folder

  • export-requirements.ps1 – exports a list of packages from your old Python into a requirements.txt-style file.

  • install-requirements.ps1 – installs packages from a requirements-style text file into the new Python.

  • copy-custom-scripts.ps1 – copies your own helper scripts from the old Scripts folder to the new one.

  • Remove-All-Python.ps1 – aggressive cleanup script that:
    • Optionally runs uninstallers for python.org installs
    • Deletes common Python directories
    • Backs up and cleans PATH
    • Optionally removes Microsoft Store Python and the Python Launcher (py.exe)
  • README.txt – usage overview and sample commands.

All scripts are written for Windows PowerShell and assume standard python.org installs (e.g., C:\\Users\\<you>\\AppData\\Local\\Programs\\Python\\Python311\\python.exe).

Option A: Migrate to a new Python version

  1. Install the new Python version from python.org and note both paths, e.g.:
    • Old: C:\\Users\\<you>\\AppData\\Local\\Programs\\Python\\Python311\\python.exe
    • New: C:\\Users\\<you>\\AppData\\Local\\Programs\\Python\\Python313\\python.exe

  2. Open PowerShell in the folder where you extracted the ZIP.

  3. Allow script execution for this session only:
Set-ExecutionPolicy -Scope Process -ExecutionPolicy Bypass
  1. Run the migration helper:
.\migrate-python.ps1 `
    -OldPython "C:\\Users\\<you>\\AppData\\Local\\Programs\\Python\\Python311\\python.exe" `
    -NewPython "C:\\\Users\\<you>\\AppData\\Local\\Programs\\Python\\Python313\\python.exe" `
    -CopyCustomScripts

This will:

  • Export your packages from the old Python
  • Upgrade pip on the new Python
  • Reinstall the exported packages into the new Python
  • Copy your .py and .cmd helper scripts from the old Scripts directory into the new one (if -CopyCustomScripts is used)

Option B: Nuke Python and start clean

If your Python installs are tangled beyond patience, or you explicitly want a clean slate, use Remove-All-Python.ps1.

⚠ Warning: This can break applications that bundle or rely on a specific Python.
Make a backup or restore point first.

Run it from an elevated PowerShell (Run as Administrator):

Set-ExecutionPolicy -Scope Process -ExecutionPolicy Bypass

.\Remove-All-Python.ps1 `
    -RunUninstallers `
    -RemoveStorePython `
    -RemovePyLauncher

What it does:

  • Searches for python.org uninstallers and runs them (with -RunUninstallers)
  • Removes common Python directories, including:
    • %LOCALAPPDATA%\\Programs\\Python
    • %APPDATA%\\Python
    • Common Program Files\\Python* locations
  • Backs up your user and machine PATH to text files on your Desktop
  • Removes Python-related PATH segments
  • Optionally removes:
    • Microsoft Store Python (-RemoveStorePython)
    • Python Launcher (py.exe) (-RemovePyLauncher)

After it finishes:

  1. Reboot.
  2. Install a fresh Python from python.org.
  3. Rebuild environments or use migration tools again to repopulate packages.

Verifying the new installation

After using the migration path or reinstalling after a wipe:

  1. Check which Python you’re getting on the command line:
where python
python --version

where py
py -0p

  1. Fix your PATH if needed so that only the new Python’s python.exe and Scripts directory are referenced.

  2. Open a project and run your usual commands (e.g., python -m pip list, pytest) to confirm everything behaves as expected.

Where to put the ZIP in your Jekyll site

For a typical GitHub Pages / Jekyll setup, you’d:

  1. Copy python-migrate-kit.zip into your repository’s assets/ folder.
  2. Commit and push that change.
  3. Make sure your Markdown link points to:
[Python Migration & Cleanup Kit (ZIP)](../assets/python-migrate-kit.zip)

Adjust the relative path if your posts live in a different directory depth.

Reusing this kit for future Python upgrades

The nice part of this approach is that it’s reusable:

  • Update the -OldPython and -NewPython paths for whatever versions you’re moving between.
  • Run migrate-python.ps1 again for normal upgrades.
  • Use Remove-All-Python.ps1 only when you truly need a clean slate.

This gives you a consistent, low-drama way to keep Python current on Windows — or start over clean — without losing the tools you rely on every day.