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My question is a very obvious one if you look at the two screenshots I've attached. The 'X' to close the Firefox browser keeps disappearing, along with the 'maximize' and 'minimize' options as well. This has been happening for months. The recurrence rate is 50/50 each time I open the FF browser. It's not just an issue with closing or minimizing a page, it also removes the access to my Windows taskbar at the bottom!! Normally, when I move my mouse to the bottom, my taskbar pops up and I can access whatever I need, BUT when the FF browser has NO 'X' at the top corner, my taskbar won't show up at all! This is finally getting on my last nerve!🤦♀

Any knowledge as to why this keeps happening?🤷♀

My FF browser is up to date, as of yesterday. My default search engine is google. My PC is still running Windows 10.....could this be the problem?

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!!!

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

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 firefox is on the latest version and up-to-date but will not access my home router which l normally us ip address. When trying to acess in edge works with no issues I am using windows 11 and all ok but wish to use Firefox And the IP adress is corect Can you advise

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

I frequently need to access logs in HTML format from a particular application. I find Firefox more comfortable for this, so I visit the parent path directly in the browser. However, the default sort order is by name; since these are logs, it's more useful for me to list them by last modified time. Is it possible to make this sort order the default when visiting file:// paths?

I've attached an image of what I typically visit for completeness.

Thanks.

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

I changed ma mozilla acc password and when i try to log in with new password on mobile "unknown error" occur. I can login on desktop with same password just fine. What to do?

I get REAL tired by the amount of resources Firefox eats up with each open window. For whatever reason, having multiple windows open prevents Facebook from loading. I'll get 1 story and a "shorts" bar but THAT'S IT. Even clicking the story to rate or comment does nothing. If I start to delete windows; it will decrease the memory usage and then it will open.

However, I DO NOT WANT TO CLOSE MY WINDOWS IN ORDER TO OPEN FACEBOOK! Firefox should not be eating up that many resources. The open windows are of text and/or picture archives. There is no sound or video playing in the multiple windows open. My system literally has 128 gigs of ram memory so it seems very odd to me that Firefox is using between 11-13% with nothing running in the 15 windows I have open.

I've noticed for awhile that when exiting Firefox (currently 150.0.3) open tabs no longer close. When I re-enter Firefox (new start) I no longer get my home page. I've tried all key combination of exiting as well as the X. I searched this community and WWWeb and found nothing usefull.

Thank you for your attention to this matter. Rodney

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.

Using firefox 140.6.0esr on Windows 10 with noScript and uBlock Origin

Infrastructure for my health insurance provider website uses a self-signed certificate. The infra has a different URL from the main page and was initially failing with "CORS failed", which turned out to be the cert issue.

I copied the infra URL from the dev tools network log and opened it directly, and accepted the invalid cert. I can see the new exception in cert_override.txt.

Then, after unblocking the site in uBlock origin, POST and GET requests to the infra URL succeed, but OPTIONS requests are still failing with "CORS failed", and security status "SEC_ERROR_UNKNOWN_ISSUER"

Is there anything else I can do so the OPTIONS request honors the exception in cert_override.txt?