Comment by coreyp_1

This one happened last night. A student contacted me because her Anaconda Jupyter notebook (installed on her laptop) just wouldn't connect to the Python kernel. (The notebook itself would load, though, meaning that the server was running fine. It's just that the kernel and its websocket was failing.) I should point out that, because of COVID-19, this troubleshooting was over Zoom, which complicated the diagnosis a bit.

She had not been using Jupyter for several months, as we have been writing stand-alone programs in class using Spyder (the editor that comes with Anaconda), and the command line, and Jupyter had worked the last time that she tried it.

We restarted everything, and still the problem was there. I helped her to update everything, but that didn't solve the problem.

Finally, I looked at the error messages in the console where the Jupyter server is running. It had a huge list of errors, all relating to the pickle library.

We had done an exercise with pickle in the class, but nobody had reported a similar problem. When we looked in her classwork directory, though, we saw that she had created a "pickle.py" file when she was testing something with pickle. But, at that point in the class, we were working in the command line, and everything (including Spyder) still worked just fine.

Evidently, this was the cause of Jupyter's problem. When trying to start the Python kernel in Jupyter, it imported pickle, and evidently it imported her test file rather than the actual library. The fix was simple: we renamed her test file, and everything worked perfectly.