Problem: You receive an error message "Unreadable Notebook: <path to a notebook> NotJSONError("Notebook does not appear to be JSON: "...")
Solution: If you look in the Jupyter directory for the notebook, you may see that there is another copy of the file with an .invalid extension, and the original is 0 bytes while the .invalid extension one is greater than 0 bytes.
If this is the case, delete the original notebook that now is 0 bytes and then rename the invalid file to original_filename.ipynb (that is, remove the .invalid extension) and try opening it. If it has the content you need then you are good to go. If not you will need assistance from someone on staff.
