I am trying to download NLTK 3.0 for use with Python 3.6 on Mac OS X 10.7.5, but am getting an SSL error:

import nltk

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I downloaded NLTK with a pip3 command: sudo pip3 install -U nltk.

Changing the index in the NLTK downloader allows the downloader to show all of NLTK’s files, but when one tries to download all, one gets another SSL error (see bottom of photo):

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I am relatively new to computer science and am not at all savvy with respect to SSL.

My question is how to simply resolve this issue?

Here is a similar question by a user who is having the same problem:

Unable to download nltk data

I decided to post a new question with screenshots, since my edit to that other question was rejected.

Similar questions which I did not find helpful:

NLTK download SSL: Certificate verify failed

downloading error using nltk.download()

You don’t need to disable SSL checking if you run the following terminal command:

/Applications/Python 3.6/Install Certificates.command

In the place of 3.6, put your version of Python if it’s an earlier one. Then you should be able to open your Python interpreter (using the command python3) and successfully run nltk.download() there.

This is an issue wherein urllib uses an embedded version of OpenSSL that not in the system certificate store. Here’s an answer with more information on what’s going on.

Please see answer by @doctorBroctor. It is more correct and safer to use. Leaving answer below as it might be useful for something else.


This will work by disabling SSL checking.

import nltk
import ssl

    _create_unverified_https_context = ssl._create_unverified_context
except AttributeError:
    ssl._create_default_https_context = _create_unverified_https_context


In Finder, search for Python 3.6.
It will appear under Application folder.
Expand the Python 3.6 folder.
Then install certificates using “Install Certificates.command”.

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To install in codestar only way is manually download modules and save them into nltk_data folder, create a lambda variable environment NLTK_DATA with valie ./nltk_data.