Jupyter notebook ImportError: No module named tornado.log

Question

I have installed jupyter and when trying to start it, I get the following error:

File "/Library/Frameworks/Python.framework/Versions/2.7/bin/jupyter-notebook", line 7, in <module>
from notebook.notebookapp import main
File"/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/notebook/__init__.py", line 25, in <module>
from .nbextensions import install_nbextension
File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/notebook/nbextensions.py", line 35, in <module>
from tornado.log import LogFormatter
ImportError: No module named tornado.log

I tried uninstalling and reinstalling jupyter, tornado, or anything I could somehow link to this error and nothing really helped. This actually used to work pretty well but it recently began throw the above error at me. Any help is greatly appreciated.

Answer 1

I just solve this problem by force reinstall tornado, using this command: pip2 install tornado --user --ignore-installed

Answer 2

Reinstalling tornado isn’t the problem; the outdated version is. Upgrade with pip install --upgrade tornado.