I'm using a Mac. I'm using Postbox as my email client (which is actually Mozilla Thunderbird under the hood). I'm connecting to my email that is hosted in Office 365 via IMAP.

Email works great.

What I want to do is to sync my contacts from Office 365 to this machine via IMAP. Is that possible?

I know that the iPhone and Mac Mail app have native exchange abilities - but I'm asking about other IMAP clients and office 365 working together. Has anyone had to deal with this?

  • No; your contacts are shared over an entirely different protocol
    – Ramhound
    Aug 23, 2014 at 0:21
  • IMAP doesn't synch contacts or calenders, IMAP synchs mail folders only. checking the FAQ's for postbox you appear to be out of luck. postbox-inc.com/faq#exchange
    – Tyson
    Aug 23, 2014 at 2:24

1 Answer 1


You can set it up using Thunderbird if IMAP is enabled in your account settings on Office365 it just requires a few add-ons for everything to work correctly.

Download Required Extensions:

Lightning: https://www.mozilla.org/en-US/projects/calendar/

Ericsson Exchange 2007/2010/2013 Calendar, Tasks, Contacts and GAL Provider: https://github.com/Ericsson/exchangecalendar/releases

Restart Thunderbird

Configure Email Settings:

Configure IMAP

IMAP server:    outlook.office365.com
IMAP port:      993
IMAP user:      [email protected]
IMAP security:  SSL/TLS

Configure SMTP

SMTP server:    smtp.office365.com
SMTP port:      587
SMTP user:      [email protected]
SMTP auth:      Normalpassword
SMTP security:  STARTTLS

Configure Office365 Global Address Book:

Open the address book and click “Add Exchange contact folder” in the menu bar

Enter the following configuration

Name:                 Office365 Contacts
Refresh:              3600
Add list to search:   Checked
Use autodiscovery:    Unchecked
Server URL:           https://outlook.office365.com/EWS/Exchange.asmx
Primary email:        [email protected]
Username:             [email protected]
Domain:               'n/a'
Share Folder Id:      'blank'

Press the “Check server and mailbox” button, it should populate “Folder base: Contacts folder” and set the Path for you

Press Save

Configure Office365 Calendar/Tasks:

Open Thunderbird File > New > Calendar Select “On the Network” Select “Microsoft Exchange 2007/2010/2013” Set calendar display settings and attach it to the configured Office365 email account (usually [email protected]) Enter the following configuration:

Autodiscovery:            Unchecked
Server URL:               https://outlook.office365.com/EWS/Exchange.asmx
Primary email address:    [email protected]
Username:                 [email protected]
Share Folder Id:          'blank'

Press the “Check server and mailbox” button, it should populate “Folder base: Calendar folder” and set the Path for you

Press Save

  • Wonderful! I googled the world over for the url for the exchange server!
    – bgmCoder
    Mar 9, 2016 at 21:51
  • Any clue as to how to set up the Instantbird chat client? superuser.com/questions/1050850/…
    – bgmCoder
    Mar 9, 2016 at 23:30
  • 1
    I wish I could upvote you more, I have been looking for this solution off and on for months now!!!
    – Logos
    Apr 11, 2016 at 18:14
  • The Office365 Global Address Book is readonly? Is it possible to add or edit contacts there? And share with colleagues?
    – tholu
    Apr 27, 2016 at 10:09
  • 3
    Note that the exchange plugin mentioned has issues and has not been updated. However, a fork exists that works great: github.com/ExchangeCalendar/exchangecalendar
    – HRJ
    Jul 8, 2017 at 6:43

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