When I first installed the Python 3 IDLE on Windows XP and tried to open the environment, I would get this error message, “IDLE’s subprocess didn’t make connection. Either IDLE can’t start a subprocess or personal firewall software is blocking the connection:
I changed my systems firewall exceptions to include IDLE, but it still did not work. I have Python 2.7 installed also because of an ArGIS software dependency. So, the next step seemed to be to run IDLE with the “-n option”, without a “subprocess”.
I have no idea what “-n option” or “subprocess” mean.
I found this forum post (which no longer seems to exist), where someone had posted very clear, simple step-by-step instructions for setting this up in Windows. Basically, you want to create a shortcut on your desktop to pythonw.exe from the installation folder of Python (e.g. C:\Program Files\Python32). When you right-click on the shortcut, modify the target to:
“C:\Program Files\Python32\pythonw.exe” lib\idlelib\idle.py -n
This works! The IDLE should start like this, with “No Subprocess”: