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Hi! Since I've installed Thunderbird on my new computer with Windows 11, I've now twice experienced the disappearance from my inbox of a bunch of emails. Never had this before with Thunderbird. Could it be something needs doing in Settings (I couldn't find any relevant options)? The emails weren't among the newest, but they were all important.

Log in with usernames and passwords are not working properly. I had to change my emails for logging and other sites because my email was stolen. Now Firefox won't let me log in properly. And the clipboard on the Android is not synced properly with the computer for Firefox. So I had to start using Chrome.

Hi,

I’m facing an issue in Firefox where some icons on my website are not updating their color correctly.

I’m using SVG icons, and the color changes work fine in other browsers, but in Firefox they seem to stay fixed.

You can see an example here: https://yourwebsite.com

I’ve tried clearing cache and checking CSS (fill/color), but no change so far.

Is this a known issue with how Firefox handles SVG or could I be missing something in the implementation?

Thanks!

如图片所示，需要用二维码登录、分享的网站，二维码全部无法正常显示！

As shown in the picture, you need to use a two-dimensional code to log in and share the website, the two-dimensional code can not be displayed normally!

after setting up a new install on another pc (ver148) and moving the profile folder over,

the only issue i have so far is the little yellow star in the folder for new mail having arrived in is not showing up. it will show the number of new msgs on the taskbar icon only.

can this be fixed?> can seem to see it in settings.

image attached of how it looks on the old pc

thanks

I love the browser and use it daily with Android phone and Linux laptop.

Concerning the new Android version, it is great. But please, bring back the select all tabs function. I like to save and backup my tabs by sharing them externally, and selecting them one by one is a very slow process.

Appreciate!

Its simple but I dont get it and firefox used to be able to it is simply like any website you have a file of anything you can slip it in just like Chrome edge opera fire fox to get it the file you have to like go in like not automatc more like MANUALLY

This problem has been on my phone for years, through many iOS versions and several iPhones. I'm guessing its something in my settings but I have no idea what. Basically, when I use Firefox on my iPhone and switch away to another program, when I switch back to FIrefox, it loses its connection to the site I was using and goes to its home page. Yes, really! If things were normal, I should be able to switch away and switch back any time at all, but it pretty much always "crashes" when I do that. But I don't want to call it a crash, because Firefox stays open and happy, but just navigates away from the URL I'd been on. What might I check in order to pursue a "fix" (I doubt that something is broken!). Thanks.

Quick followup - When I'm using FIrefox and simply put my phone to sleep (push the button on the right side, sorry, I forget the name), when I wake the phone Firefox does that same thing and leaves the page I was on and opens the home page.

3/18/26 - SOLVED! Or, rather, fixed. I finally gave up and uninstall Firefox from my iPhone, then rebooted (just for good luck) and went to Apple's App store and installed Firefox again. Set it up to sync with my desktop (Windows) Firefox, and it seems to be running fine on my phone. Whatever was causing the problem before is no longer there. Wish I had more to offer re what that problem might've been, but simply uninstalling and installing again took care of it.

I am an emeritus professor using the UVM email account tosler@uvm.edu<mailto:tosler@uvm.edu>, which I have used for many years. I use Mozilla Thunderbird (current version, “Eclipse”) as my email client and my account is configured for UVM’s Microsoft 365/Exchange Online service. After my most recent required yearly password change, although I can still receive email in Thunderbird, I can no longer send email. When I attempt to send a message, I consistently see this error: “Login to account ‘smtp.office365.com’ failed. Login to server smtp.office365.com with username tosler@uvm.edu<mailto:tosler@uvm.edu> failed.” Here are my current settings:

 *

Incoming (IMAP):

    *

Server: outlook.office365.com

    *

Port: 993

    *

Connection security: SSL/TLS

    *

Authentication method: OAuth2

    *

Username: tosler@uvm.edu

 *

Outgoing (SMTP):

    *

Server: smtp.office365.com (I have also tested smtp.uvm.edu with the same result)

    *

Port: 587

    *

Connection security: STARTTLS

    *

Authentication method: OAuth2

    *

Username: tosler@uvm.edu

I have reinstalled Thunderbird, and I have removed all saved passwords and tokens for outlook.office365.com and smtp.office365.com, restarted the program, and completed the Microsoft/UVM sign‑in prompt again. IMAP continues to work and mail arrives normally, but SMTP authentication still fails with the error above. Because:

 *

The configuration matches Microsoft 365/Exchange Online client‑submission settings, and

 *

IMAP with OAuth2 works, while SMTP with OAuth2 fails,

it appears that this may be a server‑side policy or mailbox setting, rather than a client configuration problem. What are my options? Does the University of Vermont have to change some setting on their end on my behalf? Thanks. -turner

Hi,

I’ve just setup my Mac (Tahoe 26.3.1) again as it was compromised.. Now, I was very vary of which applications, apps, logs, certificates, …. etc are installed // running.

Unfortunately, I’ve crashed my Firefox browser as I’ve seen weird names on the settings section -> certificates. I’ve just deleted them…. Once I was done, I couldn’t load any website anymore. Now, I’ve opened up a new profile (Main Profile), migrated passwords, bookmarks and checked the main settings (not touching the certificates…). The Original Profile & Profile 2 are obsolete.

Result: I can load websites again, have my bookmarks and access everything needed but now, I can’t sign back in into my Mozilla Firefox account to keep syncing everything between my Iphone, Mac and my account (just in case I’m crashing it again..).

Issue Remaining: When I’m trying to sign in entering my email address the ERROR: “Unexpected error” comes up… That wasn’t the case beforehand.

Anybody with a potential solution or steps and settings for an idiot to check if they’re correct?

Much appreciated!!!

PS: Screenshot attached from the “Original” crashed account when I’m trying to load ANY websites….

Hi folks

When I tried to start up Thunderbird this evening, it has taken me to a set-up page. I seem to have lost all the settings, all my previous (about 3000 !) e-mails in my Inbox.

I obviously don't really want to set it all up again, but it has been working for years without a problem, and then suddenly this happens. I had now a 'warning' message saying that Mozilla Thunderbird wants to make changes to your computer - do you accept? I don't want it to make any changes unless it is to revert back to how it was.

Can anybody help me?

Thanks.