Thunderbird Community Forum

I have turned off every junk filtering option in Thunderbird, globally and for each account, yet the application started and continues to mark nearly every incoming email I receive as possible junk -- even emails from MOZILLA... It is not my ISP, nor my email provider, as they are not filtering junk, either. The banner on the preview window says "Thunderbird thinks this message is Junk mail", so that tells me it is THUNDERBIRD that is doing this. How can I get the app to stop??? There are no helpful conversations in the forum, since I've tried all of the solutions that were presented. I'm about to just delete the app and use something else which is a shame since I've been using Thunderbird for probably 20 years, but I cannot continue if this problem does not stop.

Not exactly , when I delete a message on my other computer or my phone they are not deleted on my Win 11 computer . My phone and Win7 computer seem act as if they are connected , my win 11 computer doesn't know that emails were read or deleted on the other system . Yahoo email seems to work across all , just not Thunderbird .

I am using Kubuntu 24.04 LTS to run Thunderbird and trying to connect to AOL for email. AOL requires a third party app password. It recently failed to connect, then worked for a day and again failed to connect. I've had a long, friendly, but unsuccessful session with AOL tech support. They suggested that I ask Mozilla for support.

Just now, three messages were bounced from my Thunderbird inbox. The error message given was: A message was sent to you that was returned to the sender(bounced) because it would have caused your mailbox quota to be exceeded.

The following is the reason that the message was over quota:

      Quota Type: bytes in the mailbox
 Quota Available: 894.2KB
     Total Quota: 5000000.0KB

There's very little in my Inbox, but there was a lot in trash and a bunch of sub-folders I didn't need anymore, so I deleted just about everything. The little indicator at the bottom right of the screen was still red, indicating excessive messages, so I closed Thunderbird and reopened it. The red indicator is still lit up like a Christmas tree, even though I've deleted hundreds of emails from all folders, but I resent the messages (these were between my Spectrum account and my Gmail account), and they still bounced. I then rewrote the emails, reducing the number/size of attachments, but they again bounced. Other emails from outside senders are coming through just fine. I also receive my gmail account via Thunderbird and it's behaving perfectly. It's just my Spectrum email account that's acting up, although as I said, email from outside senders are coming through without a problem.

I'm doing this on my desktop, Windows 10, current Thunderbird version. I didn't go to webmail to delete any of this. I don't understand why the indicator says I'm at 99% of my quota after so many deletions.

Any and all suggestions cheerfully received!!

I recently transferred my Thunderbird email to a new Windows 11 laptop. Everything is ok, except the font size in received emails can best be described as very tiny. I've tried everything to increase the font size, but nothing helps. My screen has a resolution of 2880x 1880 Any help would be much appreciated. Thanks.

Hello. I'm trying to set up automatic config for DAV contacts and calendars located on my Nextcloud server. I've followed this doc: https://wiki.mozilla.org/Thunderbird:Autoconfiguration:ConfigFileFormat and I've managed to get at least the calendar to connect, but with one unfortunate condition: I have to open Thunderbird's about:config and set browser.opaqueResponseBlocking and browser.opaqueResponseBlocking.javascriptValidator to false.

Otherwise the request to DAV gets blocked by Thunderbird for some reason. Here is some information about my current setup: IMAP and SMTP servers are located at mail.mydomain.com, and email addresses look like user@mydomain.com. The webserver serving config-v1.1.xml is located there too, but it's behind a reverse proxy, which also proxies nextcloud.mydomain.com. When I add a new account to Thunderbird, it requests mydomain.com/.well-known/autoconfig/mail/config-v1.1.xml, so I've added a redirection rule on the reverse proxy which sends it to mail.mydomain.com and it seems to be working ok. I've added this section to the xml file:

   <addressBook type="carddav">
     <username>%EMAILLOCALPART%</username>
     <authentication>http-basic</authentication>
     <serverURL>https://nextcloud.mydomain.com/remote.php/dav/</serverURL>
   </addressBook>

   <calendar type="caldav">
     <username>%EMAILLOCALPART%</username>
     <authentication>http-basic</authentication>
     <serverURL>https://nextcloud.mydomain.com/remote.php/dav/</serverURL>
   </calendar>

(username on the Nextcloud matches the local part of the email address)

But looking at Network tab of the dev console I can still see that it's trying to get well-known dav from my top level domain. So I add redirection from there too: mydomain.com/.well-known/caldav -> https://nextcloud.mydomain.com mydomain.com/.well-known/carddav -> https://nextcloud.mydomain.com

Finally I can see the request is made to correct address: 207 PROPFIND nextcloud.mydomain.com/remote.php/dav But the icon shows it's blocked and there is a message in the JS console: The resource at “https://nextcloud.mydomain.com/remote.php/dav” was blocked by OpaqueResponseBlocking. Reason: “nosniff is true and mimeType is an opaque-blocklisted MIME type or its essence is 'text/plain'”.

I've found 2 settings I can switch off: browser.opaqueResponseBlocking = false browser.opaqueResponseBlocking.javascriptValidator = false And after that, viola - I can see my calendars showing up upon adding the account (but not contacts, I think it's a separate issue and I have to check everything).

My question is: is it possible to set this up without manually switching Thunderbird options on every machine? Some HTTP headers, perhaps?

We're currently on Windows 10 and one of the machines can't update to Win 11 as the hardware is too old. I'm looking at possibly migrating to Linux anyway, as we're already long-time TB and Firefox users. My question is about the migration process and in particular testing/checking the migration is OK, but being able to go back to Windows if needed.

If I start by installing Linux as dual-boot with Windows :

1. Can I leave the TB mailbase on the Windows partition and point the Linux version at the same location (using Settings/Server Settings/Local directory), then use TB on Linux and have the mailbase grow, on the original Windows partition? 2. If so and I need to revert, will the Windows version of TB accept the changes to the mailbase made by Linux? 3. As an issue with Linux is often that you just can't get a program you need in a Linux or browser version, could I e.g. use Linux for most of the time, then boot into Windows to use said Win-only program and at the same time use the Windows' TB until such time as I boot back into Linux? 4. Would the answers to the above differ between IMAP and POP - we generally use POP on PC with IMAP on our phones/fondleslabs, but also have an IMAP account on the PC for if needed. I can imagine that IMAP would facilitate this dual-access better than POP (or would each program have to re-subscribe to IMAP folders when you switch OS), but I'd really like to continue with POP for a fair number of reasons.

Thanks in advance

Since the error appeared that disabled the xPunge plugin (around TB 140), I have been compacting the folders in my 4 Thunderbird mail accounts manually. I wish there was a better way, but unfortunately not at this time. When I select to Empty Trash, I get messages showing quite an extensive dialog. It logs in, syncs, and even checks the folder capability of the server. When I select to Compact Files, I first get a simple message in the lower left corner "Compacting Files." Then I get messages showing each folder being compacted, and how much space was saved. It even shows reloading the last message at the end, even though the message is already there.

Since I now see this detailed dialog, I have noticed that, from time to time, the compacting fails. I get the first message, "Compacting Folders." But then nothing else. I also don't see the email message list go blank for a second when it is compacting the folder I am viewing. If I repeat the compacting folder command, it does the same thing. It appears that TB thinks the folders are already compacted, and takes no action. The only way I have found to get the compacting to work is to wait for more messages to come, delete the ones I don't want, and it will probably work on the next try. It seems to fail perhaps every 10th time or so.

Perhaps this is the same TB base code issue that is affecting xPunge? I do not get any errors, at least that I can recognize. I looked at the console, but I could not discern anything there that might be applicable - but that could be because I don't understand most of the messages there. Is there anything I can do to get around this issue? Thanks.

Since i updated to 144 Thunderbird works well once started for a few minutes and then starts eating memory and in a few minutes it uses all system memory (64GB) and when virtual memory is exhausted it crashes

Now using 145 beta with same problem.

Using google calendar and only one plugin (Clippings for Thunderbird), tried to disable plugins, calendar, hardware acceleration, tried to compact folders, clear cache, clear msf with no success

Bonjour, Hello I add new exception (see image, for every count on the servers hosted on retzien.fr, and I have to valid and valid and valid... for every access. See image. TB 140.(64 bits) Ubuntu 24.04.3 LTS AMD Ryzen 2700X x 16 16 Go Cheers

I have a Windows 7 laptop with Tbird. Replies and forwards to messages include any inline images, as would be expected.

I recently installed Tbird on a new Windows 11 laptop. Now, any replies or forwards show a placeholder for inline images, not the images themselves.

I searched - and found - user postings describing the same problem with older versions of Tbird, but no confirmed fix or setting to correct the missing inline images.

Is this an issue with the current version (144.0.1}? If not, how can I fix it? Thank you, Bruce

I am receiving, but cannot reply or send new emails through my AOL account on TB. I just keep getting the little status window showing progress, but nothing happens--I just see a progress bar trying to send. I also checked the "sent" mailbox to see if anything shows up there. It doesn't.

It's not an AOL issue because I can send emails via my iPhone's mail app. Is there a fix for this problem?

I have a new Raspberry Pi 4; OS is version Trixie (released in Oct 2025) and I installed Thunderbird apparently successfully a couple of days ago. I had asked our admin for a new email address (just for this Raspberry Pi device) and I added it to Thunderbird apparently successfully. It successfully receives all emails.

However, sending fails with the message "login to server smtp.office365.com with username ################ failed" (the message had the correct user name)

I have retyped the password many times. No success. I have edited the SMTP server settings selecting all the Authentication Methods in turn ( no authentication; normal password; Encrypted password, Kerberos / GSSAPI, NTLM and OAuth2 which was the one Thunderbird had placed there and which google told me was the right one.)

I even tried to use smtp-mail.outlook.com as my SMTP server (Microsoft suggested this), but all to no avail. Don't think I am an expert just because I tried various things. I was getting desperate. I was supposed to deliver the device yesterday. Please help. Thanks in advance.

I changed my yahoo password and can longer access this account in Thunderbird.

Now when I sign in to Thunderbird I get 'Edge To Many requests'

Unfortunately I deleted the yahoo user name and password in Thunderbird Password/ Saved Logins thinking Yahoo might automatically ask for my new password when re-starting Thunderbird

Can somebody help please.

Many thanks

Hi I was using TB 142 without problems. When upgrading to 143 ou 144.B4 I have problems sending mails to all users after some times. Usually the first mails are sent immediatly but after around 10 mails, I have very slow response (varies from 5 sec to more than 1 minute and sometimes timeout). Usually quitting TB solves the problem but this is very annoying. I went back to 140LTS and sems to have no longer this problem. This was tested on many diffrent networks. I am running under Fedora release 42

Thanks