Python "Extension activation failed, run the 'Developer: Toggle Developer Tools' command for more information"

Question

Unable to run/debug my python file. I KNOW I downloaded Python on my computer. I know I downloaded the extension in VS Code. Every time I try to run even a simple print("abc") line of code I get nothing in the terminal and a message that reads

Extension activation failed, run the 'Developer: Toggle Developer Tools' command for more information.

in addition to

Python extension loading...

and the extension never seems to finish loading. It's been hours.

How do I fix this? I am working out of Windows

Answer 1

I also had to downgrade the Jupyter extension to version 2025.6 instead of 2025.7. I have VS Code version 1.103.2 on macOS. After that, the list of Python Environments was loading correctly.

Answer 2

For example I have "Extension" named Python in the image below that gets updated or installed by vsCode automatically

1. You have to wait for the "Extensions" to be installed.
2. Make sure you have an internet connection.
3. make sure you have a fast internet connection so that it can be installed faster.
4. After installation restart "vsCode"

If it doesn't work for you, try uninstalling the extension and reinstalling it

This is all I know and it happened to me