How to Fix Error - IDLE's Subprocess Didn't Make Connection Error in Python

IDLE stands for Integrated Development and Learning Environment and is a GUI coded in Python with the tkinter library. It works on multiple platforms and has various features to work with Python scripts.

It provides a multi-window text editor and debugger, among various features. This tutorial will discuss the IDLE's subprocess didn't make connection error in Python.

Fix the IDLE’s Subprocess Didn’t Make Connection Error in Python

The full error is:

IDLE's subprocess didn't make connection. Either IDLE can't start or personal firewall software is blocking connection.

It can be encountered while opening the IDLE, and there can be various reasons behind it.

1. The first reason is a naming conflict of a Python script in the directory. This error occurs if a script exists with the same name on one of the Python packages.

   The quick way to fix this is by removing the newly created Python scripts and other scripts with the name random.py or end.py. We can also rename the scripts to prevent this error.

2. Another reason behind this error is if multiple instances of pythonw.exe are running. We can check this in the Task Manager and remove the additional instance if it is shown in the running task list.

3. The third issue behind this error is incorrect environment variables. To configure the Python environment, we need to specify the correct path in environment variables.

   If we set the HOME or USERPROFILE variables to a path that does not exist or is not writable, this error can persist.

4. This error can persist due to the Antivirus software and the associated firewall. A firewall monitors the incoming and outgoing traffic from a given network; it blocks any suspected dangerous traffic.

   Let us discuss how this plays into causing this error. Usually, the firewall asks the user for permission to access some connection. Some Antivirus software like AVAST/AVG automatically blocks external TCP/IP public connections.

   When the IDLE tries to create a connection, it gets automatically blocked by the firewall of such software. Note that not all Antivirus software has such a firewall.

   We can disable the Antivirus software or the firewall to fix this issue. We can change the firewall provider as well to work around this issue.