Thunderbird 78.6.1 is a security and bug fix update

Thunderbird 78.6.1 has been released on January 11, 2021. The new version of the open source cross-platform email client fixes a single critical security issue (the same that affected the Firefox browser and got patched in the browser in a recent update), and several non-security related issues next to that.
The new version is already in distribution and most Thunderbird clients should be upgraded automatically to the new version as the default setting is to download and install updates for the email client automatically.
Thunderbird users may select Help > About Thunderbird to check the installed version and run a check for updates at the same time.
Thunderbird 78.6.1: what is new
Thunderbird 78.6.1 patches a critical security vulnerability that affected previous versions of the email program. Critical is the highest severity rating. Users interested in details may check the security advisory page on the Mozilla website.
The release notes list one change and a good dozen fixes for various issues. The change improves certain MailExtensions functions; MailExtensions APIs are used by extension developers to create extensions for the Thunderbird email client.
As far as fixes are concerned, here is a quick overview of what has been fixed in Thunderbird 78.6.1:
- Option to run a global search is now displayed when a quick search does not return any results.
- Fixed long subject lines distorting the message compose and display windows, which made the unusable.
- Uncompleted recipient addresses were list when selecting Send.
- New message is no longer marked as "changed" when the user tabs out of the recipient filed without making any changes to it.
- Fixes for account auto-discover functionality when using Microsoft Exchange servers.
- Stability fixes for LDAP address books.
- Messages with invalid vcard data were not marked as read when viewed in the preview window.
- Could not add TLS certificate exceptions for XMPP connections in chat.
- Two calendar fixes:
- system timezone was not detected properly sometimes.
- blank descriptions when editing a single occurrence of a repeating event.
- Unnamed fixes for the message search toolbar.
- Several printing fixes.
- Visual consistency and theme improvements.
Now You: do you use Thunderbird? Did the update install fine on your devices?


You said that Outlook isn’t your main email client, so which is your main one?
I think its thunderbird
It is Mozilla Thunderbird.
Awesome! This actually solved my problem… what a stupid bug.
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.
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!!!!
Solved my issue! 6 years later and this is still problem…
Fantastic. Thank you. Size did the trick.
This solved my Outlook problem, too. Thank you. :)
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.
You are a god – thank you!
thanks a lot…. work like charm.. :-)
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
Excellent post. This had me baffled even trying to accurately describe the problem. This fixed it for me.
Thank you
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 :-)
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.
I’ve been tried to sole this problem for 12hours. Your comment about changing the display of screen helped me a lot!! Thanks!!
Thank you…don’t know why this happened but your instructions helped me fix it. Running Windows 10 and office pro 2007
Great tip! Thanks!
Worked for me, too – thank you!!!
It’s Worked for me, too
thank you very much!
I had a similar issue with Outlook 2013 on Windows 10 and this helped me to fix it. Thank you very much!
Thank you so much. Solved!
Considering you published this in 2012, incredible not been debugged by Microsoft.
Thank you again. M
This problem was faced by only one user logging to TS 2008 r2 using outlook 2010.The issue was resolved.
Thanks.
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.
Thank you, this worked !!!!
Man, you are a fucking god. Thanks a lot, what an annoying bug!!
Awesome, this post solved the issue. Many thanks!