Thunderbird 60: extension and theme changes

Martin Brinkmann
Jul 6, 2018
Email, Thunderbird

The Thunderbird development team released the last version of the 52.x branch a couple of days ago. The next version of Thunderbird will be Thunderbird 60.0 if no last minute minor version is released before it.

Thunderbird 60.0, just like the Firefox 60 release was, is a big release that moves the email client from the old Extended Support Release to the new 60.x development version.

Thunderbird 60 will introduce a lot of new features and changes. Some of these affect the handling of extensions and themes. The changes are not as dramatic as those introduced in Firefox 57 but users may still run into compatibility issues.

Probably the biggest change in regards to extensions is that Thunderbird will only load extensions that are marked as compatible with Thunderbird 60.0 explicitly. Add-ons that are not will be disabled and if you try to install an extension that is not marked as compatible with at least Thunderbird 60.0, you will get the "could not be installed because it is not compatible" error message.

thunderbird 60 extension not compatible

There is a solution for that though, as you can disable strict compatibility checking to install extensions that are not marked as compatible with Thunderbird 60 explicitly.

Here is how that is done:

  1. Select Tools > Options from the menu bar. If the menu bar is not displayed by default tap on the Alt-key on the keyboard to display it.
  2. Go to Advanced > General.
  3. Click on Config Editor.
  4. Search for extensions.strictCompatibility
  5. Double-click on the preference.

A value of true means that strict compatibility checking is enabled in Thunderbird, a value of false that it is disabled.

thunderbird extensions.strictCompatibility

While that won't make incompatible extensions compatible with the browser, it ensures that compatible extensions that are not listed as compatible by their authors can be installed and enabled.

Once you have flipped the preference to false, you can install extensions to find out if they will install this time.

All extensions listed on the official Thunderbird add-ons website  list minimum and maximum compatibility information. Any extension that is listed as compatible with Thunderbird 60.0 or higher will install and run just fine in the email client when version 60.0 gets released.

Extensions that lists a lower version of Thunderbird can still work in Thunderbird 60.0, but those need the flip of the preference unless the author pushes out an update before the official release of Thunderbird 60.0.

You may notice that Options buttons are missing on the Add-ons Manager page. You can display the Add-ons Manager with a click on Tools > Add-ons.

The development team moved the options to Tools > Add-ons Options instead where you find all extensions with options listed. Just select the one that you want to modify and the options open in a new window.

I have no information why the change was made; it feels less intuitive in my opinion as I cannot change the settings of several extensions without having to select Tools > Add-ons Options each time to select another installed extension.

As far as themes are concerned, Thunderbird 60.0 supports WebExtensions themes which you can install just like any other theme in the email client.

Now You: What's your take on these changes?

Thunderbird 60: extension and theme changes
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Thunderbird 60: extension and theme changes
The Thunderbird email client development team will release Thunderbird 60.0 soon. The new version will introduce changes to extension and theme handling.
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  1. JMGG said on January 19, 2012 at 8:25 am

    You said that Outlook isn’t your main email client, so which is your main one?

    1. BalaC said on January 19, 2012 at 9:42 am

      I think its thunderbird

    2. Martin Brinkmann said on January 19, 2012 at 10:15 am

      It is Mozilla Thunderbird.

  2. Salaam said on September 24, 2012 at 9:52 pm

    Awesome! This actually solved my problem… what a stupid bug.

  3. Claud said on December 19, 2012 at 2:08 am

    If this is the same bug that I’ve encountered, there may be another fix: (1) hover over open Outlook item in Taskbar, cursor up to hover over Outlook window item, and right-click; (2) this should give you Restore / Move / Size / Minimize / Maximize — choose Move or Size; (3) use your cursor keys, going arbitrarily N/S/E/W, to try to move or size the Outlook window back into view. Basically, the app behaves as though it were open in a 0x0 window, or at a location that’s offscreen, and this will frequently work to resize and/or move the window. Don’t forget to close while resized/moved, so that Outlook remembers the size/position for next time.

    1. Lynda said on February 12, 2013 at 3:37 pm

      THANK YOU Claude!!! I could get the main window to launch but could not get any other message window to show on the desktop. You are my hero!!!!

    2. Chad said on November 20, 2018 at 4:24 pm

      Solved my issue! 6 years later and this is still problem…

    3. Ivan X said on January 21, 2021 at 4:50 pm

      Fantastic. Thank you. Size did the trick.

  4. Andrew said on October 26, 2013 at 7:06 am

    This solved my Outlook problem, too. Thank you. :)

  5. Charles said on December 7, 2013 at 7:23 pm

    Thank you so much, this started happening to me today and was causing big problems. You are a life saver, I hope I can help you in some way some day.

  6. garth said on November 7, 2014 at 7:13 pm

    You are a god – thank you!

  7. Faisal said on February 9, 2015 at 10:09 am

    thanks a lot…. work like charm.. :-)

  8. Simon said on March 24, 2015 at 11:36 pm

    Yah…thanks Claude. I’ve been having the same problem and tried all the suggestions…your solution was the answer. It had resized itself to a 0/0 box. Cheers

  9. Olu said on April 14, 2015 at 1:35 pm

    Excellent post. This had me baffled even trying to accurately describe the problem. This fixed it for me.
    Thank you

  10. Coenig said on July 23, 2015 at 7:36 am

    Thanks a lot for the article. Don’t know why it happenend, don’t know how it got fixed, but it was really annoying and now it works :-)

  11. Fali said on January 20, 2016 at 4:19 pm

    Thanks a lot. I was facing this issue from past 3 week. I tried everything but no resolution. The issue was happening intermittently and mainly when I was changing the display of screen ( as i use 2 monitors). The only option i had was to do system restore. But thanks to you.

    1. MIki said on January 10, 2019 at 11:54 am

      I’ve been tried to sole this problem for 12hours. Your comment about changing the display of screen helped me a lot!! Thanks!!

  12. Christina said on January 20, 2016 at 6:14 pm

    Thank you…don’t know why this happened but your instructions helped me fix it. Running Windows 10 and office pro 2007

  13. Oz said on July 22, 2016 at 3:20 pm

    Great tip! Thanks!

  14. Tracy said on September 1, 2016 at 4:48 pm

    Worked for me, too – thank you!!!

  15. shawn said on September 9, 2016 at 10:25 am

    It’s Worked for me, too
    thank you very much!

  16. Jari said on October 31, 2016 at 11:53 am

    I had a similar issue with Outlook 2013 on Windows 10 and this helped me to fix it. Thank you very much!

  17. Michel H said on November 30, 2016 at 11:08 pm

    Thank you so much. Solved!
    Considering you published this in 2012, incredible not been debugged by Microsoft.
    Thank you again. M

  18. Ziad Bitar said on January 9, 2017 at 2:00 am

    This problem was faced by only one user logging to TS 2008 r2 using outlook 2010.The issue was resolved.


  19. Anonymous said on February 15, 2017 at 5:24 pm

    Great tip. Thank you!!!! If it helps, I had to use the Control Key and the arrow keys at the same time to bring my window back into view. Worked like a charm.

  20. Rochelle said on March 6, 2017 at 11:59 am

    Thank you, this worked !!!!

  21. anom1234 said on May 20, 2018 at 11:20 pm

    Man, you are a fucking god. Thanks a lot, what an annoying bug!!

  22. JC said on October 12, 2020 at 2:14 pm

    Awesome, this post solved the issue. Many thanks!

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