Thunderbird Community Forum

I am currently using Thunderbird version 140.10.2 esr. (32bit) I understand that to latest version is 150. I also understand that, from version 145, Microsoft Exchange accounts are supported natively by Thunderbird.

I am using a generic desktop PC running Windows 10 Pro (22H2)

I am having difficulties with an Exchange account using the OWL add on.

I would like to upgrade my Thunderbird to the latest version and use the native support for Exchange accounts. I would also, if possible, like to upgrade to a 64bit version.

When I follow the instructions (Help/Update Thunderbird) the pop up reports that 'Thunderbird is up to date'.

I can't see a way forward at present, can someone assist please.

My business has two domains. I can send email to a Gmail account holder using the primary domain with no issues. But amy emails from what I call the "secondary" domain below are treated as spam. This occurs with two different email addresses using the secondary domain.

Both domains are hosted with Bluehost. Exhaustive research has revealed the following:

• Settings in Thunderbird are exactly the same, e.g. ports, security, SSL/TLS, etc. for each domain.
• There is no subject line or content that could possibly be regarded as spam.
• MXToolbox indicates that the secondary domain is not on any blacklist.
• Extended support via Bluehost reveals that SPF, DKIM, and DMARC records are all correct.
• Email sent to a Gmail account using the CPanel (Roundcube) is not flagged as spam. Only emails sent via Thunderbird are flagged.
• Emails sent to a Gmail account from the secondary domain using my mobile phone, but still on the same network/IP address, are not flagged as spam.
• If I first send an email to one of the secondary domain emails FROM Gmail, then reply to it, the reply is not flagged as spam.

After many hours of head scratching (and later, head banging), I am pretty much at my wit's end with this problem. I'm an electronic engineer but this one is definitely out of my wheelhouse. Any help would most certainly be appreciated!

Thanks in advance, Don

Hi, I've been using Thunderbird latest version for a few days. Too much I have a problem that is bothering me. I have 20 accounts and if I choose Unified Folders, on the six of Tunderbird I see only a part of the Accounts and precisely 14. To solve my problem I also used the "Unified Folder Debugging" add-on but it didn't solve the problem. Why do I have this problem? I would like to use Unified Folders but I can't do it because I don't have any Accounts. Thanks for some info.

I have 3 different hotmail accounts. And tried to set them up in a newly installed thunderbird app on windows (10,sorry not up to date). In the beginning I had 2 out of 3 working, but the last one is my business account and it didn't connect. I tried many different ways to get it working, and now only the 1st one is still connecting correctly. The second one also doesn't connect anymore and is giving me the: "The connection was refused when attempting to contact localhost." or Authentication error: Unable to log in at server. Probably wrong configuration, username or password.

I know for sure password and username are correct. I have added thunderbird to exceptions in firewall. I also tried turning the firewall off. no changes. I have no idea where it got so messy but can someone guide me in this? Most of it I do not understand so it is obvious I made mistakes.

After updating Thunderbird to version 150.0.2, I can no longer connect to my lolipop.jp mail servers.

Symptoms:

• Both IMAP and SMTP stopped working at the same time
• Webmail works normally
• Multiple mail accounts are affected
• Thunderbird times out when connecting to the servers
• The issue started immediately after updating to Thunderbird 150.0.2

Settings tested:

• IMAP: imap.lolipop.jp / Port 993 / SSL-TLS / Normal password
• SMTP: smtp.lolipop.jp / Port 465 SSL-TLS and Port 587 STARTTLS
• Tried Thunderbird Safe Mode
• Tried reinstalling Thunderbird
• Tried disabling Norton security/firewall temporarily
• Same issue persists

Could this be a known issue with Thunderbird 150.0.2? If so, is there any workaround or planned fix?

Thank you.

I have been using T-bird for years successfully until lately. We have multiple email addresses in Comcast and Gmail, but lately our passwords that we have been using and know are correct because they are written on paper and Keypass, are being changed somehow so that they will no longer work. When we look at the saved passwords in Thunderbird we see some have been changed on a certain date that we did not do, and the password listed now must be about 200 characters long. Then when we go to change the password, it may be listed as changed. Then when we try to send a message with that email address, we get an error message saying, for example, smtp.googlemail.com and a wrong username/address completely. I can find no way to correct the username email in any settings in Thunderbird. I have searched the Thunderbird HELP files many times, but am unable to find any of this addressed anywhere. After trying to fix these problems for most of 3 days now, I have get rid of Thunderbird for an email client that works correctly!!!

Clearly, this is a very basic question which has undoubtedly been answered before, but I haven't been able to find it. If Thunderbird had an old-style Help feature with an index, I could probably look it right up. But coming to the forum is the only option the program gives me.

Hello,

Despite the fact that I have set Thunderbird to display messages as plain text, my needs are not being fully respected. If the message contains some form of markup, presumably HTML, the font size is not what I have chosen. Generally, the font size is smaller than what I have specified in the Thunderbird settings.

This is unacceptable. It is a usability / accessibility issue. If the user chooses Plain Text and sets a font size, they have done that for a reason. Which is accessibility. If Thunderbird ignores the needs of users and applies styling rules to messages, that is a failure state.

Is there some way to actually, truly, absolutely display all messages as plain text in a specified font, weight, and size? If not, what is the protocol for reaching developers so that they can respond to this issue?

Thank you

With 03.04.2026 they began to notice that the attached emails in eml format (the attached emails have attached documents, mostly pdf) sent from yandex mail stopped opening. Everything used to open well. Eml also does not save to disk. If you send the same files via Gmail, everything opens. Program version 150.0.1

Hello,

I am on Thunderbird 150.0.2 for Windows.

I am really suffering here. I need to change the font weight of unread messages. In a non-threaded list.

The default weight I get with my preferred font (Trebuchet MS) is not bold. It is BLACK. When I say BLACK, I mean ultra bold, display font, heading weight. Heavier than the boldest font that even exists in the font family. Thunderbird is creating this ultra mega black font by taking the bold font variant and applying a faux bold effect to it. The result is that the text is so heavy that it takes up twice as much horizontal space as the ordinary bold font variant. This becomes a usability issue because it's not possible to see the date, sender, and subject at the same time.

I have struggled and strived with userchrome.css. Spent hours combing through forums here and elsewhere. I've already enabled the mystery setting in the config editor. I put userchrome.css where it is supposed to be.

I saw a blog post from Mozilla that says "userchrome.css is not supported". What is the actual meaning of this? That it has been actively blocked from working anymore, ever, for anyone? Or that users are taking risks if they create userchrome.css? Why can't developers speak plain language? "Not supported" could mean many things.

When I go to the Style Editor, userchrome.css does not exist there. Which leads me to believe that user customizations are absolutely deprecated and we are not permitted to use userchrome.css.

I tried editing some of the rules in the Style Editor, but could not determine any way of actually storing the changes. When I click Save, I get a dialog where I can **EXPORT** the file. But I can't seem to actually save the changes, because CSS files do not appear to exist in the installation directory. It must be compiled into some library.

This is extremely unsatisfying and super frustrating. Just getting straight answers to things is super difficult, nothing stays the same for more than a couple months, and up to date information either does not exist or is not found by any search engine.

So, please help. I just need to change one setting, the font weight of unread messages. Since Thunderbird is allegedly open source, I thought I would have some ability to make such changes. But the Style Editor doesn't seem to actually be an editor, but merely a read-only interface to precompiled rules? If I wanted to change the font weight of unread messages, would I be forced to compile my own version of Thunderbird? I'm not competent to do that, and it would probably either prevent updates, or the updates would break my changes.

Please help, I am super desperate. I need to see the date, sender, and subject all at the same time. That doesn't seem like an unreasonable ask.

I would gladly pay for an email client that gives me control over my data *and* allows me to control the UI, but apparently that doesn't exist.

Ever since the latest update, when I hit send for an email. It says it cannot send, I cancel, hit send again and it goes through. I have to try sending EVERY email twice.

I just installed a new router and all of a sudden nothing is working properly on my PC. Among other things, I need to fix Thunderbird, and for that I need to find where my thunderbird profile is. The instructions I've seen say to go to troubleshooting information, find profile folder, and click on "open folder." When I do that, nothing happens. (I told you installing the router appears to have broken everything--I don't know how that happened, especially since I was on the phone with tech support for the router for install), and I'm no closer to finding the profile file. I can enter %appdata%\roaming\thunderbird\profiles but that shows me two different profile directories and I don't know which one is the right one. How can I find the correct file and why doesn't troubleshooting information just show me that?

This only recently started happening. This has been tested on 3 different computers. Windows 10 Pro on all three.

With VPN on: Bluemail works fine.

Thunderbird can connect and download messages, but when I try to send a message, it gives an error.

With VPN off:

Bluemail and Thunderbird both work fine.

Drgan Maric, 74, Belgrade, Serbia. This is my self-taught English.

I use Thunderbirad for years, including small donation when I start to use it. Since a few days I can not open WebMail from cPanel of Namecheap,

Nothing is changed in both servers and ports. In Account Settings Outgoing Server has an option to TEST connection for server. Result failed.

An Attachment is an immage of TEST and RESULT FILED.

In this age, with broken spine and almost immovanle, it makes me very frustrated. Coud you plase reaolve this issue and make Thunderbird to work properly and peace in my mind,

Français: Bonjour, Presque tout mes icônes dans la barre des tâches, programme ouvert, sont bleu. Comment changer directement la couleur de l'onglet de Thunderbird dans la barre des tâches de Windows. Ce serait bien de pouvoir choisir pour retrouver facilement Thunderbird et lire mon courrier. Christian

English Almost all my icons in the taskbar, for open programs, are blue. How can I directly change the color of the Thunderbird tab in the Windows taskbar? It would be great to be able to choose so I can easily find Thunderbird and read my emails.

SIMPLIFY THUNDERBIRD IT IS EXCESSIVLY COMPLEX. I CANNOT EVEN SEE HOW TO MOVE MESSAGES FROM THE INBOX TO THE RELEVANT FOLDER IN MY LIST. I PERSONALLY BELIEVE FIREFOX AND THUNDERBIRD ARE OVERCOMPLEX AND NEED SIMPLIFIED. SIMPLES. WHY CANT I COPY AND PASTE THE VERSION NUMBER. BLOODY ARESHOLES . AS I SAID IT IS BLOODY OVERCOMPLEX. AT THIS POINT I AM CONSIDERING GIVING UP ON WHAT IS CLEARLY AN OVERCOMPLEX PIECE OF SOFTWARE THAT REALLY DOESN'T LOOK GOOD EITHER AND THERE IS NO OFFICIAL SUPPORT SO WILL HAVE TO LOOK FOR AN ALTERNATIVE. COMPLETE WASTE OF SPACE TOO MANY COOKS SPOIL THE BROTH COMES TO MIND THIS IS WHAT WE HAVE HERE

I have been using Thunderbird for 10+years and was able to set up Gmail accounts without any problem. Currently, there are 3 Gmail accounts configured under Thunderbird and those all are working fine. I needed to add one more GMAIL account, everything seems to go through OK, but near the end, it fails with an error message: "Unable to login at the server. Probably wrong configuration, username or password."

I also installed Thunderbird on MAC and repeated the same steps to configure GAMIL account and got the same error message.

The same errors occur if I configure APP PASSWORD in Gmail and then try to configure GAMIL account in Thunderbird using APP PASSWORD. Still got the same error message.

HELP PLEASE