Pi’s Blog

My blog about Thunderbird and GSoC 2008

Duplicate contacts in Thunderbird 3

As the author of a synchronization extension for Thunderbird 2 and 3, I get a lot of questions about duplicate contacts.  Duplicates are more common than ever  with the explosive popularity of mobile devices.

There is a fairly popular Duplicate Contact Manager Extension on AMO, but it hasn’t been updated recently, won’t work in Thunderbird 3, and comments mention some bugs, possibly including one that was present in gContactSync 0.2.0a1.

I have not found a way to contact the author, Marian Steinbach, to offer my assistance with updating it for Thunderbird 3.  It looks like the Google Group doesn’t have much activity.

I can reuse a good chunk of code from gContactSync which would allow it to work in Thunderbird 2 or 3, but I would most likely package it as a new extension to not force everyone to install gContactSync just to remove duplicate contacts.  I had some primitive duplicate detection code in 0.1.x, but it was inefficient and only checked e-mail addresses since that’s what Google used to identify duplicates.

So, I have three questions.

  1. Would there be enough interest to warrant new duplicate contacts extension?
  2. Would anyone else like to work with me to develop one?  I already have plenty of code for working with contacts and the address book; it would just need an intuitive, customizable front-end and an efficient way to find duplicates.  I’m just a bit busy with work, gContactSync, online classes, and a possibly emerging social life.
  3. Does anyone have a way of contacting the original developer?

April 6, 2009 - Posted by | GSOC, thunderbird | , ,


  1. This sounds like something that’ll be very useful. I don’t see why you shouldn’t include it in gcontactsync since as you say most of these duplicates are a result of syncing from different platforms. I guess that your engine resolves these duplicates somehow itself before sync.

    Comment by dead1nside | April 7, 2009 | Reply

  2. I have like 900 contacts in my google account. If I had a way to easily clean them up, group them by how often I communicate with them, and keep them up to date it would be a compelling reason to move to Thunderbird.

    Comment by Aubrey | April 7, 2009 | Reply

  3. I tried the duplicate contact addon but it doesn’t work properly. If you have 2 same email address in one group it will not find the duplicity.

    Comment by Petr | April 7, 2009 | Reply

  4. +1 for a separate extension.

    Comment by Blair McBride | April 8, 2009 | Reply

  5. This would be awesome to have, I have problems with the other extension because I have more than 1000 contacts.

    Comment by Atlanta Video Production | April 22, 2009 | Reply

  6. A duplicate manager is essential given the escalating and imperfect sync options out there. Perhaps a maintenance mode that digs a little deeper than just names would be helpful (i.e. address fields, etc.). Nearly half of my 600 active business contacts do not have an e-mail address or “work” phone – just a mobile number, because it syncs with my phone. Searching duplicate field that are null isn’t helpful at all.

    It would also be nice to create a new contact by duplicating another, then changing at east one field before saving. Major time saver in pre-vcard pims.

    Comment by Bob | May 1, 2009 | Reply

  7. Thank you for updating contact manager for thunderbird 3.! And also for trying it.

    Comment by Ilaria | June 16, 2009 | Reply

  8. Hello,

    Someone has also made a patch to this extension, which seems to work on Thunderbird 3b2, I tested it, perhaps it could be good to integrate it :


    I do not know how Mozilla works when an author doesn’t update an extension and someone else wants…

    Best regards.

    Comment by Valeryan_24 | July 7, 2009 | Reply

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