Exchange EWS Provider Add-on for Lightning (Thunderbird/Seamonkey)

(2014-10-21) As you can read I no longer maintain this add-on. But the guys from Ericsson have taken over maintanance. You can get new versions from their github page: https://github.com/Ericsson/exchangecalendar/releases.

I will keep my pages online for the archive.

(2014-05-08) I do not maintain this add-on anymore. Anyone who would like to take over can use the source at Github for it’s own fork. Thanks to everyone who has supported and helped to get the add-on to it’s current state.

!!! The next information is old and outdated !!!

lightningexchangecalendarWelcome on the website with the only add-on for Thunderbird and Seamonkey which will add access to you Exchange calendars, contacts and Global Address List (GAL). It is an add-on for the Lightning Calendering Add-on and will allow you to communicate with an Exchange 2007, 2010 and 2013 server using the Exchange Web Service (EWS) interface.You can access any Calendar, Task or Contacts folder on the EWS server in an easy way. And also manage your “Out of Office” settings.


  • Version 3.2.x for Thunderbird 12 up to 27 (tested up to and with 27).
  • Version 3.1.x for Thunderbird 6 up to 17 (tested up to and with 17).
  • Version 3.0.x for Thunderbird 6 up to 17 (tested up to and with 17).
  • Version 2.x.x for Thunderbird 6 up to 14 (tested up to and with 14).
  • Seamonkey 2.6.1 – 2.20.
  • Lightning add-on
  • This add-on.
  • Access to an Exchange Webservice Server (EWS) with an username, password and/or primarySMTP or email alias.
  • The Exchange Webservice Server of Exchange 2007, 2010 or 2013. Or that from Microsoft Office 365 (see FAQ for howto).

The latest stable version (3.1.3 released 25th of October 2012), which can be newer than on the Mozilla repository, can also be downloaded from this site: [download id=”13″]. If you find problems please report them to the bugzilla. What has changed please see [download id=”14″].

The latest development version (3.2.x) can be downloaded through this link: [download id=”17″]. Because of it’s development nature some new functionality might only work half because it is still in development. Or it is a bug fix which is still in it’s testing phase. If you find problems please report them. See Reporting Bugs. What has changed please see [download id=”18″]. (On GitHUB this is the “master” branch).
Please try this version and turn on offline cache (below calendar settings). When you already use offline cache please turn it first off for the calendar. Restart TB and then turn it on again. It should stay in sync now.

All versions can be downloaded from the download page.

Changed in version 3.2.0-BetaX:

  • Completely new Event Interface. We now use our own which is an extension of the one default in Lightning.
  • New TimeZone function for matching between the Exchange TimeZone and the Lightning TimeZone.
  • Almost complete rewrite of task/todo handling.
  • It will now try to show the Exchange time zone for the start and end times as close as it can match it to the one in Lightning.
  • Added the Exchange SOAP Autodiscovery functionality. This will be used first and when it fails it will fall back to the old POX Autodiscovery.
  • Can follow redirectAddr response from Exchange.
  • Will try Basic authentication as default when available.
  • Fixed problems with opening attachments when having multiple items open.
  • Adjusted reminder configuration to what is possible in Exchange.
  • Address autocompletion for composing emails or adding attendees to calendar event.
  • Showing of icon/image for contact in address book.
  • Added Exchange Task details.
  • Fixed editing Out Of Office messages with HTML editor.
  • New Exchange server version detection.
  • Rich text description editing/viewing including link editing and following.

What can it do:

  • Support Exchange server 2007, 2010 and 2013 (Office365).
  • Sync Calendar, Task/Todo and Contact items from an EWS (Exchange) server.  Syncing is done on a user settable poll interval. It will track changes on the server and update the local memory cache.
  • Create, modify and delete calendar events and task/todo items. They will get synced immediately with the EWS server.
  • Contacts are currently read-only.
  • Search the Global Address List (GAL).
  • Use contacts and GAL in address auto completion.
  • During creation of a new calendar you can use the Exchange Autodiscover functionality (when enabled on the Exchange server) to find the right server and mailbox settings. Selecting the right folder is easy with the build-in folder browser.
  • You can access any Calendar, Task or Contacts folder on your EWS server as long as you have the right primarySMTP or alias email address and enough permissions for the used user.
  • Let it poll your inbox for meeting invitation request or cancellations. They will show up in your calendar.
  • Manage how meeting invitations or cancellations are automatically handled (responded to).
  • Add as many calendar objects as you wish and Lightning will allow.
  • Manage “Out of Office”settings for each calendar mailbox.
  • Import ICS files.
  • Export to ICS files. (Experimental: new since 1.8.0a4 not a full calendar yet only local memory cache)
  • Manage and view attachments.
  • Edit event/todo description with rich-text. Colours, fonts, links, etc…
  • User availability (Free/Busy) information.
  • Currently in Dutch (Nederlands), English, French (Français) (Thanks to Dominique Fillon) , Swedish, Japanese and German (Deutsch) (Thanks to Christian A. Meyer) localizations. When you would like to make a translation for your language please let me know .
  • Can work with Basic, Negotiate and Kerberos authentication. Please see this page for an explanation. No NTLMv1 or NTLMv2 on Linux.

Known issues:

  • When Thunderbird is started or a new Calendar is added it can take some time to load and cache the items from the EWS server. Be patient it will all be loaded. After it is loaded it is fast because it will work with an local temporary memorycache.
  • Because of the previous slowness. When you try to change, add or delete an item during loading this change might take some time to be synced to the EWS server.
  • And those mentioned in the bugzilla.
  • It is not possible to accept or decline assigned tasks. Microsoft does not provide the necessary API calls for this. Even OWA cannot do this. Only outlook.

For questions please send them to Ericsson but first read the FAQ section or have a look at the Forum pages.

If you think of a nice feature or functionality which currently is not available have a look at the feature request page.

If you find a bug in this add-on please report it at https://www.1st-setup.nl/bugzilla/.

319 Responses to Exchange EWS Provider Add-on for Lightning (Thunderbird/Seamonkey)

  1. BEC says:

    With the latest updates of v50+ I’ve been unable to confirm any meetings/send responses. I reverted back to v49 to fix the problems. (Win 7, Thunderbird v24.1.1, Lightning v2.6.3)

  2. Josh Davis says:

    TB 24.2.0
    Windows 7 x64 SP1
    EWS 3.2.0-B71
    Exchange 2003 and also Office365 Live.

    It seems like when this goes to update calendars, it hangs TB.
    I notice this because I write long-winded emails.
    I can’t even type in TB until it’s done refreshing.
    I had the sync time set to 360 seconds, but as of a couple of weeks ago, it reverts this to 60 seconds.

    Will try B81. Didn’t realize it didn’t auto-update.

  3. Matz says:


    Exchange EWS Provider Add-on: 3.1.3
    Lightning: 1.2.3
    Thunderbird: 10.0.12 ESR
    OS: Win 7

    First a little “bug”: the printer icon isn’t a printer, it’s a broom in lightning tab …

    I tried to manage my GAL but the add-on showed only my added outlook contacts. Isn’t it possible to manage the GAL in this release? Or what is my mistake?

    Please keep the support of Tb10 alive!!!
    Thanks in advance!

    • admin says:

      The EWS add-on does not do anything with the printer icon. This looks more like a bug in Thunderbird/Lightning (https://bugzilla.mozilla.org.

      Why are you not updating to the latest ESR release TB 24.2.0?
      I do not know if we can support TB10 longer. There is no active support for it anymore from Mozilla.

  4. Kalle Larsson says:

    Just wanna say this is the BEST plugin around (together with Lightning). Thanks a LOT!

  5. dodgy says:

    It doesn’t work for me. It seems I’m not able to find the correct server url.

    – outlook.com (office365)
    – thunderbird 24.2.0
    – Exchange EWS Provider 3.2.0-Beta75

    I tried following server url’s:
    https://m.hotmail.com (testconnectivity.microsoft.com)
    https://pod51011.outlook.com (https://kb.wisc.edu/helpdesk/page.php?id=29243)
    https://dub111.mail.live.com/ (adress from adress bar when logged in in outlook.com)

    I’m not shure, but does office365 support ews? I red an article which told it only sopports eas…

    If anyone could help me, I would highly appreciate it!

  6. Nira Pite says:

    I am very grateful to you, 1st Setup. I have been suffering before I have found your plugin. Thanks a million, and keep up the good work 🙂

  7. Juergen says:

    I got a numeric IP-Adress from our administrator for our Exchange server. This is ok for Android clients but EWS seems not to accept this format (xxx.yyy.zzz.aaa):
    :[Exception… “The URI is malformed” nsresult: “0x804b000a (NS_ERROR_MALFORMED_URI)”
    Thunderbird is not a supported platform by our company so I have to deal with it for my own.
    Any help here?

    • admin says:

      The EWS interface is served by an Internet Information Server. This EWS interface does not have to be installed on the same server as the exchange server(s). What you could try is https://xxx.yyy.zzz.aaa/ews/exchange.asmx as the server url. Only the ip address is not right.

      Second. Does your company offer access to the Outlook Web Access (OWA) or also called the webmail interface of Exchange. This is normally something like https:///OWA. If so try https:///ews/exchange.asmx
      I hope this helps.

  8. Juergen says:

    Hi admin,
    thanks for your help. I entered “https://aaa.bbb.ccc.xxx/ews/exchange.asmx”. Still no success:

    Fehler bei der Abfrage des Servers und des Postfachs:HTTP Client error 403: Forbidden

    Seite kann nicht angezeigt werden
    A:link {
    FONT: 8pt/11pt verdana; COLOR: #ff0000
    A:visited {
    FONT: 8pt/11pt verdana; COLOR: #4e4e4e

    <META content=NOINDE
    (Code: -19)

    Seems as if it doesn't find what it expects. But what more chances are there to find out the correct URL?…

    • admin says:

      Please try the url in Firefox. It should ask you for your credentials and show a xml page. When not please try to find out which authentication mechanism is being used on your EWS (Exchange) Server.

      • Sam A says:

        I am getting the forbidden issue now as well. I have uploaded a log file if you need it:

        This all started maybe a week or so ago. When I go to the url through a browser, it works fine. I put in my u/p and get an xml list.

        • Sam A says:

          I forgot to mention, this is using the office365 service. We do not host an exchange server.

          • Sam A says:

            Ok, looks like microsoft changed what “app” can access the ews settings. I used the generic url of:

            It is now working again. Hopefully this helps someone.

          • admin says:

            Thank you for this solution. I just found out myself I had to change the server url to outlook.office365.com to get the calendars working again. Microsoft changed the server url for full read/write as the old only allows to see free/busy info.

  9. Cayenne Woods says:

    Unable to add exchange calendar
    Have tried both ‘exchange autodiscovery’ and ‘Check server and mailbox’ options

    In both cases, it hangs, with no error

  10. Alex says:

    Why isn’t an up-to-date version oublished at addons.mozilla.org? (Just curious)

    • admin says:

      First is that the review process ad Mozilla takes between 4 and 8 weeks. My release cycle was much higher so I introduced my own update meganism.
      Second is because of our own implemented update meganism it violates one of Mozilla’s policies for being allowed into the add-on repository.
      I hop this answers your question.

  11. Bruce Ashford says:

    I have configured EWS Provider to access my exchange server’s GAL but now cannot find a way to remove this configuration. Can you help?

    I’m using TB 24.2.0 on Linux (CentOS 6.5).

    • admin says:

      If you only would like to remove the GAL option go into the address book of Thunderbird. Double click on the exchange contacts folder and the properties folder should become visible. Now uncheck the “add global address list….” option and save.

  12. Bruce Ashford says:

    Hi and thanks for the quick answer! I expected that there would be a sensible way of doing this but, I do not have an ‘exchange contacts’ folder in Thunderbird address book. No new address book appeared after I turned on EWS Provider’s GAL access. However, automatic e-mail address lookup/completion is happening.

  13. Vadim P. says:

    I’m having two reminders for EWS-connected meetings not being dismissable – dismiss button does nothing, closing the reminders window makes it come back. The Thunderbird error console does not mention anything.

    Could this be an issue with Thunderbird or EWS?

    • admin says:

      This probably is in EWS and/or Exchange server. Do you have access to Outlook? do you see the reminders there too?
      do you have offline cache active for the calendar if so. Turn of offline cache. restart TB and then see what happens.

  14. RB says:

    Hi, thank you for starting this project. My calendar connects well with my Office365 calendar. I cannot seem to get the plugin (latest version beta 77) to work with my account. When I go into my address book and click on the exchange address book, none of the addresses populate. When I write an email, only addresses that I’ve used previously appear.

    How do I configure this add-on for lightning to work with microsoft’s exchange server’s contacts?


    • admin says:

      Did oyu add an Exchange contacts folder?
      Did you check the GAL option for the contacts folder. (is in the contacts folder settings)

  15. RB says:

    Somehow my post was deleted from yesterday. I love the addon, thank you very much.

    My Exchange Contact list in my Address Book isn’t working. Am I doing something wrong or is this feature broken / not implemented?


  16. Rosana says:

    I’ve been using Lightning and Exchange EWS Provider for a long time, and it works perfectly, but I missed GAL contacts. I’m working with an Office 365 account.

    Last week I started feel the Thunderbird and very slow, consuming a lot of resources. Maybe it was an update.

    Looking for information I started visiting add-on Webpages and I saw the beta 3.2.0 with GAL access. It’s just what I was looking for.

    Currently I have:
    * Thunderbird 24.4.0
    * Lightning 2.6.4
    * Exchange EWS Provider-3.20-Beta77

    And now I can see all the groups and users at GAL that I couldn’t see before. I know it’s a beta version, so it can hang, so I’m experiencing some freezes when I try to see Exchange contacts properties, or for example I can see all my contacts and address window, but I can’t when I’m creating a new email.

    Do you have an expected date to run new stable version? Now I know that it’s active, but I can’t install it to other devices until it’s working properly. I’d like to thank you for this add-on, the only way a user can work with Thunderbird and Office 365.

    By the way, after updating Exchange EWS Provider, I have a normal resources use again from Thunderbird.

    Thanks and regards,

    • admin says:

      Good to hear it working. When you use the GAL option it always needs to communicate with the Exchange server to collect data. It does not cache it localy. Second there is a bug report about the speed of GAL. See Bug 316

  17. Scott says:

    If you’re having issues, you might try a clean – new thunderbird PROFILE. It worked for me.

    I had reverted to and stayed on thunderbird 24.0 because the 24.1 and Lightening release on Linux broke EWS. Last week when I finally checked to see if things were updated the site indicated that issues were fixed and testing was successful upto Lightening 27.

    so I updated everything and again the calendar stopped working. EWS logged no errors that I could make out. But it was not pulling up the calendar data. I could not open calendar properties nor could I delete the calendar and build a new one.

    When I started browsing around in the ./thunderbird/.. extensions/../calendar-js/ directory I found a number of JS files that were for Davmail that I had tryed to use at one time and several other files that just did not seem like they should be there.

    The safe way to ‘clean that up’ was to build a NEW profile and copy over my address box and stored email. It took all of 10 minutes to get back to 100% running and EWS runs like a top, mail is actually FASTER now, etc.

    So, in the future instead of just copying my entire ./thunderbird profile directory to new systems,. I’m going to build a NEW profile and copy over the address box, settings, etc. Much cleaner and fixed at least one major issue for me.

  18. Brendon says:

    I have been trying 3.2.0-Beta77 using Thunderbird 24.4.0 on a Mac running OS X 10.9.2.

    I really like that hyperlinks within an invite are now active.

    I’ve found however that when I receive a meeting cancellation, sometimes it is deleted from my calendar, other times (rather annoyingly) the invite is kept but the title is changed to “Canceled: …..”. Meeting reminders for the invites changed to “Canceled:” also pop up as if the meeting is on.

    This cancellation behaviour does not happen in version 3.1.3

    • admin says:

      The removal of canceled meetings is handles by the Exchange servers and not the add-on. The add-on is only following the Exchange server for these. I know that you configure options within exchange or through OWA on how cancelations should be handled by the exchange server.

      I will add a feature request to the bugzilla for not showing reminders for canceled meetings.

      • Brendon says:

        I can’t find the setting. If I use OWA, I get the option to “Remove from Calendar” when I receive a cancellation. This option doesn’t seem to translate into Lightning / Exchange Add-on. Sometimes a “Delete” button appears (but not always) and when I select it, it does not always work.

        In 3.1.3 when an individual meeting or meeting in a series is cancelled, a strike-through is placed through the meeting entry. I found that very useful.

  19. Brendon says:

    To be a bit more specific, the “Cancelled:” invites appear in my calendar when I receive a cancellation for one meeting in a daily/weekly/etc meeting series.

  20. Joshua says:

    Does this addon still work? It was suggested by Postbox and I get “this is not compatible with Postbox” when I attempt to install it.

  21. Amélie says:

    Event updates don’t seem to work with my calendar.

    When I receive an update, Lightning displays a message “This message contains an update to an existing event” with 3 buttons “Accept” / “Decline” / “Tentative”.
    I click on “Accept”, the message changes to “Event has been updated”. But nothing is changed in the calendar and if I go back to the invite message it says again “This message contains an update to an existing event”.

    I am using Exchange EWS Provider 3.20-Beta77, Lightning 1.9.1 and TB 17.0.10.

    Do you have any clue what’s wrong?
    Thanks for your help.

  22. Sridhar Ayengar says:

    Hi. Thanks for a great add-on.

    When I use the address book in Seamonkey, I go through the process so that the email client can search the GAL. That part works. However, the folder never shows up in Seamonkey’s address book. Is that supposed to happen?

    • admin says:

      No it should show. the add-on has not been tested with the latest versions of Seamonkey. Please create a bug report for this using instructions on this page

  23. rob price says:

    Thanks for this great app!
    I cannot seem to get a sync to happen between my local 2013 Exchange server and EWS provider.
    newest version of thunderbird seems to work fine for email and contacts but no calendar sync. Also OWA works fine (https://mail.myserver.ca/owa/)
    Here is my Exchange server info..

    using latest Lightning and EWS provider.
    When synchronize button is pressed, nothing happens.

    Thanks for any help and appologies if this is answered elsewhere.


  24. Ludio says:

    Why is this not in the Mozilla “Add On” store?

    • admin says:

      They do not like the update functionality which I have build into it. They only allow their own update functionality. There fore Mozilla does not allow the add-on to their store.

  25. anonymous says:

    could you also provide a thunderbird addon that connects to a MS Sharepoint server?

  26. David says:

    Really cool work! I’m using the EWS Provider since some time now.
    If I could propose some feature request:
    * delay first sync after thunderbird startup for some (configurable) seconds
    * When a web proxy denies access to the (https) calendar, several certificate warnings are popping up and are blocking TB (could maybe be solved with going offline / online and resync afterwards again?)
    Maybe I shall report a bug on this?

  27. Kaylee says:

    I can not find the “out of office” function anywhere on Exchange EWS 3.2.0- not in tools or events/tasks – can’t find it on a search either. Any ideas?

  28. EricV says:

    Too bad the development ceased before thunderbird 30 is out. I tested the latest git code but without success on 30.0b1 (after patching install.rdf).

  29. Art says:

    Is it possible to add a shared calendar? I do not see shared calendars in Calendar Folder below folder base 😐

    Are they even supported?

  30. Mathijs says:

    For all those people who still use this addon even tho it isn’t maintained anymore.
    Mozilla disabled NTLMv1 for there Gecko Engine.

    On Linux and Mac you can enable this again by going to Preferences > Advanced > “Config Editor” > search for ntlm and change the preference “network.negotiate-auth.allow-insecure-ntlm-v1” to true.

    Now it should work again.

  31. Engin says:

    Is there any way we could ask for the developer to maintain, at whatever low level he can, at least to keep basic functionality working? Currently, the addon does work for almost everything one needs it. Unfortunately, there is no good replacement for it.

    In my case, I would abandon my work’s Exchange calendar, and switch entirely to a Google calendar, but I can see that many others cannot do that.

    Thank you for taking the addon this far, and I hope you can work on it in the future.

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