Can’t Install Python on Windows — How to Fix

You downloaded the Python installer, ran it, and something went wrong — maybe an error popped up, or Python just doesn’t seem to work after installation.

Installing Python on Windows should be straightforward, but a surprising number of things can trip you up along the way.

Don’t worry, you’re not the only one. This guide walks you through the most common installation problems and how to solve each one.

Why Python installation fails on Windows

Python installation issues on Windows usually come down to one of these causes:

• The installer was downloaded from the wrong source: Using unofficial downloads can lead to corrupted or incompatible files
• Antivirus or Windows Defender is blocking the installation: Security software sometimes flags the installer as suspicious
• “Add Python to PATH” was not checked: Python installs fine but can’t be found from the command line

Solution 1: Download from the official site and install correctly (most common fix)

The most reliable way is to start fresh with the official installer.

1. Go to the official Python website

# Open this URL in your browser
https://www.python.org/downloads/

Click the yellow “Download Python 3.XX” button. Do not download Python from other websites.

2. Run the installer with the right settings

# On the first screen of the installer:
# ☑ Check "Add Python 3.xx to PATH" ← VERY IMPORTANT
# Then click "Install Now"

If you see “Setup was successful”, the installation worked. Make sure the PATH checkbox is checked — this is the most commonly missed step.

3. Open a new Command Prompt and verify

# Open a NEW Command Prompt window (old ones won't work)
python --version

If you see “Python 3.XX.X”, everything is set up correctly.

Solution 2: Antivirus or Windows Defender is blocking installation

If the installer fails with a vague error or gets stuck, your security software might be interfering.

1. Temporarily disable real-time protection

# Open Windows Security (search "Windows Security" in the Start menu)
# Go to "Virus & threat protection"
# Click "Manage settings"
# Turn off "Real-time protection" temporarily

Remember to turn this back on after installation.

2. Run the installer again

# Right-click the installer file and select "Run as administrator"
# Check "Add Python 3.xx to PATH"
# Click "Install Now"

Running as administrator ensures the installer has permission to write to all necessary folders. If installation completes without errors, you’re good.

3. Re-enable your antivirus and verify

# Turn real-time protection back on
# Open a new Command Prompt
python --version

If the version number shows up, the installation was successful.

Solution 3: Use the Microsoft Store version

If the standard installer keeps failing, the Microsoft Store offers a hassle-free alternative.

1. Open the Microsoft Store

# Search for "Microsoft Store" in the Windows search bar
# Search for "Python" inside the Store
# Select "Python 3.xx" and click "Get"

2. Wait for the installation to complete and verify

python --version

The Microsoft Store version handles PATH configuration automatically and avoids most installer-related issues. If the version shows up, you’re done.

If nothing works

If none of the above solutions help, try these steps:

• Uninstall all existing Python versions first: Go to Settings → Apps, search for “Python”, and uninstall every version you find. Then install fresh
• Check your Windows version: Python 3.9+ requires Windows 8.1 or later. If you’re on an older version of Windows, download Python 3.8 instead
• Restart your computer: Sometimes a reboot is all it takes to clear out leftover files from a failed installation

When asking for help, include:

• The exact error message you see
• Your Windows version (search “winver” in the Start menu)
• Which Python installer you downloaded (32-bit or 64-bit)

Summary

• Always download Python from the official site (python.org) and check “Add Python to PATH”
• If installation fails, try running the installer as administrator or temporarily disabling antivirus
• The Microsoft Store version is a reliable alternative that handles setup automatically

Related articles:

• python-path-windows.html (How to fix Python PATH on Windows)
• pip-install-error.html (How to fix pip install errors)