Thunderbird Community Forum

Hi, I am wondering if there is an add-on for Thunderbird that makes it send messages like Outlook without the connection timing out under poor network conditions. Outlook simply holds the message in the Outbox until it has sufficient service to send it. With Thunderbird if there is a poor connection, it's always popping up time out errors in such a case.

When I try to log into my Add-ons for Thunderbird account, I'm shifted to Firefox.

I can log into the account just fine but, since it's not open in TB, I can't get my add-ons loaded automatically.

My Signature Switch extension recently started turning itself off. That means that every new email I write, I have to turn on the Signature Switch. For some reason, it no longer remembers it's supposed to be on between emails so for every new email I write I find it switched off again.

I'm hoping its just a setting somewhere. Can anyone help me figure out how to fix it? If not, is there a decent replacement?

We use the Add-On "Mail Merge" (https://addons.thunderbird.net/en-US/thunderbird/addon/mail-merge/?src=search) to create lists for Outgoing mail.

It adds the individual messages to the Outbox and then when you "Send Unsent Mail", Thunderbird spools them one at a time.

Noticed with a recent update to 144.0.1 this behavior hangs. It will send out maybe 5 messages and then just stick at "Sending Message" under the Activity Manager view. If you close Thunderbird and the Activity Manager and reopen, you can then do "Send Unsent Mail" and another 5ish will send before the behavior repeats.

I attempted deleting the Global Database from Profile directory, rebuilding, uninstalling/reinstalling 144.0.1, eliminating AV scanning, turned off Indexing, emptied out directories, nothing seems to change the behavior. Sending individual messages works fine.

Rolled back Thunderbird to the 140.4.0esr release and the program will send normally without the hang. Updated to 141.4, also works fine. Updated to 142.4, this is the first version I see the behavior. I collected a Performance Profile which can be reviewed at https://share.firefox.dev/4nxcltl for the issue happening on the 142.4 version.

With standardtexter, I can add audio with... src="http://www.islandnet.com/~bitron/Sounds/laughter.wav" but it will not add from a file... src="file://D:\$Laughs\Laughing Gopher\laughter.wav"

Is this a limitation, or my src is wrong? Can this be added to the extension so I can add from my file? Thanks.

I'm trying to get the calendar app working in a new Thunderbird installation. Here are my notes on what I tried: https://addons.thunderbird.net/en-us/thunderbird/addon/lightning-calendar-tabs/versions/ Download lightning_calendar_tabs-3.8-tb.xpi (latest version) to C:\Users\ken\Downloads In Thunderbird: Tools --> Add-ons --> Gear icon --> Install add-on from file --> C:\Users\ken\Downloads --> lightning_calendar_tabs-3.8-tb.xpi "about:addons Lightning Calendar Tabs could not be installed because it is not compatible with Thunderbird 144.0.1." Any suggestions?

Can someone explain why the emails I write are still spell-checked, even though I have unchecked "Check spelling before sending message" and "Check spelling continuously" in "Settings" countless times? Even the Thunderbird add-on "Replywithheader" still checks spelling, even though I have unchecked "spell-check" there too. I don't want spell-checking, but I can't get away from it! It really bothers me.

Is there an extension or add-on that can search like the old Eudora does? The default search does not seem to search thru headers or all email messages This is important for us when we need to find the Senders IP numbers so we can ban the spam emails

Dear Thunderbird Team,

I am writing to report a critical issue with the Thunderbird Extension API where it returns stale, cached data instead of live folder contents for Gmail IMAP accounts.

Issue Description The browser.messages.list() and browser.messages.query() APIs are returning outdated message data from 2016-2021, completely ignoring the actual current contents of my Gmail IMAP inbox. While Thunderbird's UI displays current emails correctly, the extension API serves permanently cached old data.

Evidence of the Bug What Thunderbird UI Shows: Current inbox with emails from today and recent weeks

Real-time folder contents

Proper folder synchronization

What Extension API Returns: Only 100 messages total (artificial limit)

Messages exclusively from 2016-2021

No emails from 2022-2025 present

Completely ignores current folder contents

Technical Details: Profile: /Volumes/Data/Mail Files/Thunderbird/Profiles/aq8q4la7.default-release/

Account: Gmail IMAP (imap.googlemail.com)

Folder: account1://INBOX

API Used: browser.messages.list(folderId) and browser.messages.query()

Steps to Reproduce Set up Gmail IMAP account in Thunderbird

Write extension using browser.messages.list() API

Compare API results with actual folder contents

Observe API returns stale cached data from years ago

Debugging Attempted We have tried:

Deleting all .msf index files

Clearing folderCache.json and global-messages-db.sqlite

Removing cache folders (cache/, cache2/, startupCache/)

Rebuilding folder indexes

Using different API methods (messages.query vs messages.list)

None of these resolved the issue - the API continues to return the same stale dataset.

Impact This completely breaks any extension that needs to access current folder contents, such as email tracking, automation, or filtering extensions.

Request Please investigate why the Extension API serves different (and outdated) data compared to Thunderbird's main UI, and fix the API to return actual live folder contents.

Thank you for your attention to this critical issue.

Best regards, Hasan

Greetings! I read everywhere that we must install the Lightning add-on to use the calendar feature in Thunderbird. But when I search for this add-on, I get a bazillion options, none of which appears Lightning. There is something called Lightning Calendar Tabs that keeps coming up. Is this it? Doesn't seem so.

Where can one download/install the Lightning add-on?

Thank you.

I am a M365 - leaver, and working several months now with Thunderbird/LibreOffice/Nextcloud. Sometimes I'm proud of what I learned and can do with the new software. Sometimes I'm a little lost in the woods.

I'm using the add-on Quicktext to insert default html text, like a template, in some of my my emails. One of the templates is a notification for my customers to inform them the invoice they received from me is not yet paid.

In the former software I was used to click in my template on a datepicker to insert the senddate of the invoice. I tried to insert a html-datepicker. This appears in the email, but is send to the reciever as a datepciker, not as the date I choose.

My question. Is there a way to insert a datepicker in a template like Quicktext, or is there a better add-on for this goal?

I've used Thunderbird with the Owl add-on for Exchange/Outlook accounts for several years. Recently I've found when I open Thunderbird on my laptop, a tab opens for each account, apparently showing the Outlook web page for each account. This is great, but on the same version of Thunderbird (140.3.1esr) on my desktop, that doesn't happen. I can't see how to open these tabs there, or even how to reopen one of these tabs on my laptop, except from Go->Recently Closed Tabs. Am I missing something? What controls this behaviour?

Good morning, after the 143 update the Send Later add on is marked as not compatible, but I see now that also with 143.01 It persist and that the version 10.7.2 should be compatible but TB does not want to install it, no matter what citing "is not compatible". i tried all suggestions from the developer (the add is compatible to 144) but to no avail. He thinks this is an issue with TB.

Can you please help ?

Kind regards

Sorry to bother in here, and dont know if its the correct place.

I developed a add-on for my use, and dont mind to share with others.

How can I share it in the addons manager? Is it possible, what do i need to do?

Do add-on settings get backed up when backing up a profile? I always have to manually install my add-ons when reinstalling a profile. I have one add-on that is a pain to set back up (Identity Chooser), and I have assumed the settings for it are lost.