Moved from jupyterlab/jupyterlab#14142, per this comment that suggests that the fault is in this file in CPython.

Description

On a Windows 10 computer with Firefox set as the default browser, running jupyter lab causes a dialog box to appear: "Internet Explorer / This action is restricted. For more information, please contact your system administrator."

After I dismiss the dialog, Microsoft Edge pops up with the JupyterLab URL specified in the terminal.

On this Windows machine, there is no default browser set.

Reproduce

1. Set up a new Windows 10 machine with no default browser.
2. Install JupyterLab via Conda (conda install jupyterlab).
3. Run JupyterLab from the terminal (jupyter lab)
4. See behavior shown above.

Expected behavior

If no default browser is selected, the jupyter executable does not attempt to launch any browser, but instead displays the URL to load with no further action. This would be similar behavior to when the user runs jupyter lab with the --no-browser parameter.

Linked PRs

• gh-102520: Document browser fallback behavior on Windows #103212