Auto Zip Attachments Extension for Thunderbird 3.0

UPDATE: I have updated the extension to support the current version of Thunderbird (version 3.1).

What makes Thunderbird (TB) a kick-ass desktop mail client is its flexibility that makes it extensible through various addons/extensions and plugins.

One of my favorite extensions since TB1.5 was the Auto Zip Attachments, which automatically compresses (zip) attachments on-the-fly. This is especially useful for email messages sent with MS Excel or Word format attachments, wherein compression ratio are usually high. No more need to manually zip the files from the file explorer before attaching the same to email to save on bandwidth, which likewise translates to speedier file transfer.

Unfortunately, the developers of this extension appear to have forgotten about it and failed to update the same to keep it abreast of the new and more robust Thunderbird 3.0. It’s only compatible upto TB2.0. It seems that changing the max version in the install.rdf file is not enough. Instead, it involves editing further another file deep into the .xpi file, as described in one of the reviews for this extension.

Following the instructions from the reviews/comments on how to edit the .xpi file to make it compatible with TB3, I successfully installed the Auto Zip Attachments extension into my own TB install. I took the liberty to make that modified extension available here for everybody’s consumption. Download link below:

Download and unzip the file, then install to your TB3 desktop client. Would appreciate feedbacks for any problems or issues encountered. Hope we enjoy Thunderbird 3.0 more with this extension.

0 thoughts on “Auto Zip Attachments Extension for Thunderbird 3.0”

  1. It doesn’t work with mac os 10.6.4 or I didn’t succeed to install in TB3

    Have you a solution for mac ?

    1. Hi Pink, I hope you can elaborate what really was your problem, then I can try to replicate it in my system. Then, I can offer solutions if I could come up with one. Thanks!

  2. Hi Deuts,
    I tried to post my settings and how to reproduce the problem, but I always end up with a white screen when I press the “send button” here.
    Maybe you can tell me an e-mail-address where I can sent my comments to ?

    1. Hi Pink, it actually worked for me. I tried it in my system. I tried checking the option in the add-on to “Zip automatically when sending” and so far it worked. Maybe you can start by describing what OS you are using.

  3. Hello Deuts,
    I am using two computers:
    one with Win XP and one with Win7.

    AutoZip Options ==> Tab “Advanced”:
    * Automatically Zip while sending –> YES
    * Use user-defined settings –> YES
    * Confirm automatic zipping –> YES

  4. Yes, manual zipping via the zip button works.

    I also de-activated all other Add-Ons for testing. But didn’t solve the problem.

    Thunderbird’s error console also doesn’t show any error concerning Auto Zip.

    1. Seriously, Pink, I don’t know how I can help you without actually sitting at your desk and do the troubleshooting. How about trying to create a new profile and install the same plugin in there. Or re-install thunderbird and delete your user profile for the previous install.

  5. Thanks for the tip.
    With a new test profile, automatic zipping while sending works.
    I am wondering what’s wrong with my default profiles (because I have the same problem on two different computers).
    I will have to investigate…

    Sorry for reporting a bug. Seems not to be one.

  6. Hi Deuts,
    I found the reason why automatic zipping while sending doesn’t work in my case:

    I set Thunderbird’s pref:
    mailnews.sendInBackground –> TRUE

    Maybe you can have a look at this ?
    Thanks a lot 😉

    1. Yes that mailnews.sendInBackground is false in mine. Great that you actually found the culprit. At least it can be useful to other people who might find their way into this site. Thanks!

  7. Hi.
    I’ve found this site googling…

    Here is an alternative to Auto Zip Attachments:”Auto Compress File”.

    Everything has been completely rewritten from scratch, but the main idea was to provide a “modern” alternative to this former useful but obsolete addon.


    I can garantuee better flexibility and maintenance (i am the developer!).

    ACF works for MAC, and ACF works also for background sending !


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