Installing Thonny
Here are some of the most common problems installing Thonny on Windows computers.
Missing or Corrupted Installer
Description: Sometimes the Thonny installer file is not completely downloaded, becomes corrupted, or is flagged incorrectly by antivirus software.
Solution:
- Re-download the installer directly from the official website: https://thonny.org
- Make sure the file is not blocked by antivirus software or Windows Defender.
- Right-click the installer, select “Properties,” and check for a message at the bottom saying “This file came from another computer…” and click “Unblock” if present.
- Run the installer as an administrator.
Insufficient Permissions
Description: Thonny may fail to install or run properly if the user account lacks administrative privileges, especially when trying to write to system directories.
Solution:
- Right-click the installer and select "Run as administrator."
- If you're in a managed environment (e.g., school or work PC), contact your IT admin for permissions or install in your local user directory.
Thonny Not Launching After Installation
Description: After a successful installation, Thonny may not start due to misconfigured environments or missing dependencies.
Solution:
- Try launching Thonny from the command line (
cmd
) with:
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Python Not Found or Wrong Version
Description: Although Thonny includes its own Python interpreter, some installations can conflict with system-installed Python, especially if PATH is misconfigured.
Solution:
- Use the bundled version of Thonny that includes Python (recommended).
- Avoid modifying the PATH manually unless you're managing multiple Python versions.
- Check the
Tools → Options → Interpreter
setting in Thonny to verify which interpreter is being used.
Serial Port Not Found (for MicroPython/PyBoard)
Description: When trying to use Thonny with a microcontroller like Raspberry Pi Pico or ESP32, the serial port may not appear.
Solution:
- Install the correct USB drivers (e.g., CH340 or CP210x).
- Try a different USB cable (many are power-only).
- Restart the computer after driver installation.
- Use Device Manager to check if the device is recognized and assigned a COM port.
Thonny Crashes or Freezes
Description: Thonny can crash or become unresponsive due to plugin issues, corrupted user settings, or insufficient memory on older machines.
Solution:
- Reset Thonny’s configuration: Run the following command in a terminal:
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C:\Users\<YourName>\AppData\Roaming\Thonny
* Update Thonny to the latest version, or try installing a previous stable version.
Thonny Plugin Installation Fails
Description:
When trying to install additional packages or plugins via Thonny’s Tools → Manage Packages
, the installation may fail.
Solution:
- Ensure you're using the bundled Thonny Python interpreter.
- Use the “Simple” interface when prompted for installation options.
- If needed, install the package manually in the command line using:
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Windows Defender SmartScreen Blocking Thonny
Description: The SmartScreen filter may prevent Thonny from running by showing a warning message.
Solution:
- Click "More info" and then "Run anyway."
- Consider whitelisting Thonny in your security software if this becomes recurring.
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