imapclient error on Windows - windows

Question

Environment that I'm having trouble on: Python 2.7.11 on Windows10 (patched up to date). Python installed via a msi. I've checked PATH settings in settings, and it's set to c:\Python27.
This works on Mac:
from imapclient import IMAPClient
IMAPClient("imap-mail.outlook.com", use_uid=True, ssl=(True))
But on Windows, if barfs like so:
Traceback (most recent call last):
File "test_outlook_imap.py", line 3, in <module>
IMAPClient("imap-mail.outlook.com", use_uid=True, ssl=(True))
File "C:\Python27\lib\site-packages\imapclient\imapclient.py", line 152, in __init__
self._imap = self._create_IMAP4()
File "C:\Python27\lib\site-packages\imapclient\imapclient.py", line 164, in _create_IMAP4
self._timeout)
File "C:\Python27\lib\site-packages\imapclient\tls.py", line 153, in __init__
imaplib.IMAP4.__init__(self, host, port)
File "C:\Python27\lib\imaplib.py", line 173, in __init__
self.open(host, port)
File "C:\Python27\lib\site-packages\imapclient\tls.py", line 159, in open
self.sock = wrap_socket(sock, self.ssl_context, host)
File "C:\Python27\lib\site-packages\imapclient\tls.py", line 126, in wrap_socket
ssl_context = create_default_context()
File "C:\Python27\lib\site-packages\imapclient\tls.py", line 109, in create_default_context
context.load_verify_locations(cadata=certs)
File "C:\Python27\lib\site-packages\backports\ssl\core.py", line 654, in load_verify_locations
self._ctx.load_verify_locations(cafile, capath)
File "C:\Python27\lib\site-packages\OpenSSL\SSL.py", line 528, in load_verify_locations
_raise_current_error()
File "C:\Python27\lib\site-packages\OpenSSL\_util.py", line 48, in exception_from_error_queue
raise exception_type(errors)
OpenSSL.SSL.Error: []
Is this to do with Window's handling of certificate chains?
Incidentally, it does the same for imap.gmail.com in the place of the Outlook domain.

Answer 1

This is not a final answer, but the work around that I've found is to uninstall imapclient and install an older version. Version 0.13 (and 0.11) worked for me, however after upgrading to 1.0.1 I got the same error message that you posted.
To uninstall imapclient with pip, run:
pip uninstall imapclient
To install the older 0.13 version with pip, run:
pip install imapclient==0.13
To verify the version of imapclient, from the interactive shell run:
>>> import imapclient
>>> imapclient.__version__

Answer 2

Here's a workaround that worked for me (Python 3.5, Windows 10), and which doesn't require downgrading:
from backports import ssl
from imapclient import IMAPClient
context = ssl.SSLContext(ssl.PROTOCOL_TLSv1_2)
server = IMAPClient('imap.gmail.com', ssl=True, ssl_context=context)
The above code was derived from the developer's workaround here, but I found I only needed the one line defining context to make it work. Specifying other SSL/TLS protocols also worked.
Update: This bug should be fixed as of IMAPClient 2.x