Five Advanced Thunderbird Tips

Martin Brinkmann
Mar 24, 2008
Updated • Mar 23, 2014
Email, Thunderbird

Thunderbird is my mail software of choice even though I do have various web mail accounts. I simply prefer my mail to be on my computer and not on a server somewhere on the Internet. I run a fairly customized version of Thunderbird and I would like to share five advanced Thunderbird tips with you that I implemented in my version.

I'm going to show you how to reduce the size of the attachment icon, change the reply header, password protect the message pane of IMAP accounts, only display folders with unread messages and how you can protect Thunderbird with a master password that works similar to the Firefox master password.

If you have a tip on your own reply with it in the comments, I'm always looking for great ways to improve my work flow in Thunderbird.

Reduce the Size of the Attachment Icon

The attachment icon in Thunderbird is fairly large and takes up lots of space beneath the message in Thunderbird. You can change the large icon into a smaller icon in the Thunderbird configuration. A click on Tools > Options loads the Configuration. Click on the Advanced tab and there on the Config Editor button, this loads the about:config menu that you know from Firefox.

Filter for the name mailnews.attachments.display.largeView and double-click it to set the value to false. This will reduce the icon noticeably.

Change the Reply Header

The standard reply header in Thunderbird is "name wrote". It is possible to customize or disable the reply header. This option can be found in the user.js file in the Thunderbird profile folder. Search for a heading named // Change the reply header and change it accordingly. Everything is explained in there.

To go to the profile folder, select Help > Troubleshooting Information > Show Folder.

Password protect the message pane of IMAP accounts


You can password protect the message pane of your IMAP accounts in the Thunderbird configuration. Just open the about:config window again like you did in the first tip. Enter the preference mail.password_protect_local_cache in the filter and change the value from false to true by double-clicking it.

Only display folders with unread messages

I use a rather complex folder structure that gets in my way if I want to just read through all the unread mails. You might have noticed the <> icons above your folder pane that are on the right side of the All Folders text. If you click on one of them you switch to a different folder view mode and the first one when clicking on the right arrow is the Unread Folders mode that displays only folders that contain unread messages.

Update: To display only unread messages, select View > Folders > Unread from the menu bar.

Set a Master Password in Thunderbird

thunderbird master password

If you do not set a master password anyone can access your mail passwords. Please do not confuse this with disallowing anyone access to your mails. This only prevents users from retrieving new mail and from accessing your mail passwords. You can set the Master Password on the Security > Passwords Tab in the Thunderbird options.


Tutorials & Tips

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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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