I have already configured Thunderbird on Win10 to access my Office 365 account. Sending and receiving mail (via IMAP) works, and TB shows correctly the subscribed folders.

Now I'd like to configure TB to access Office 365 contact directory / addressbook via LDAP, and hence, when I'm writing a message, have the "autocomplete" feature for email addresses of local recipients.

How can I do that?


The easiest way that I have found is to use the Davmail connector.

This is a Java applet that runs in the background on your Windows 10 PC. To Thunderbird it looks like IMAP for receiving email, SMTP for sending it, and LDAP for address book queries. On the Office365 side it talks the native protocols.

I've been using it for about five years now, and IME it's solid and reliable.

The installation pre-requisite is Oracle Java. Download the JRE from the Java download page. At the time of writing the appropriate download file is jre-10.0.1_windows-x64_bin.exe. (If you get asked to create an Oracle account, there is a small-print "Skip this step" if you know to look for it.)

Configuration settings for Davmail

  1. Main

    • Exchange protocol: Auto
    • OWA (Exchange) URL: https://outlook.office365.com/EWS/Exchange.asmx
    • Local IMAP port: YES 143
    • Local SMTP port: YES 25
    • Caldav HTTP port: YES 1080
    • LDAP port: YES 389
    • Trash keep delay (POP): 30
    • Sent keep delay (POP): 90
    • IDLE folder monitor delay (IMAP): 2
    • Everything else: NO or Blank
  2. Network

    • Bind address:
    • Everything else: NO or Blank
  3. Advanced

    • Edit Caldav notifications: YES (you may prefer NO)
    • Display startup banner: YES
    • Enable KeepAlive: YES
    • Everything else: NO or Blank

Configuration settings for Thunderbird

  1. Tools > Options > Addressing

    • Directory server: [Edit directories...] > Add

      1. General

        • Name: Office 365
        • Hostname: localhost
        • Base DN: ou=People
        • Port number: 389
        • Bind DN: {your Office365 email address}
      2. Advanced

        • Don't return more than: 100 results
        • Scope: Subtree
        • Search filter: (objectclass=*)
        • Login method: [Simple]

This question is pushed by duckduckgo as the main One.

I had some problems using davmail (mainly with icontray). And the Calendar was not Easy to use.

So I've search deeper. And I found TBSync https://addons.thunderbird.net/fr/thunderbird/addon/tbsync/ It works Out of the box. No technical configuration no background process. I just gave my account and password and everythings else was detected. Adresses and Calendars are now gracefully working.

The only tips you should know with tbsync is that after installing it (as an Tools>add ons) the configuration menu entry is in Edit>Synchronisation settings (TBsync).

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