Fixing Jupyter Notebook startup error

I previously wrote about Jupyter Notebooks here.

Before the MacOS Sierra 10.12.5 update, to launch Jupyter in your browser, you only needed to do this:

  1. Open Terminal.
  2. Enter the desired directory.
  3. Activate your virtualenv (if using one).
  4. At the command line, type:
jupyter notebook

A new window would open in your default web browser, and there were all your Jupyter files.

But after the MacOS update, instead we got an execution error: localhost doesn’t understand the “open location” message. And the browser window did not open.

The way to fix it (do it once) is here.

Note: In the config file, I had to search for 

#c.NotebookApp.browser =

instead of the string the author provided.