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I can only open my emails by right clicking it and opening in new window. Also keeps asking for password every time I go on Thunderbird. Have tried solutions on the help pages and online for both problems but not much use. Some things on account settings and security are not there to select. Is it correct that if I uninstall Thunderbird and then reinstall it the same problems will be present?

For some reason Firefox remembered my phone number and is now trying to use it as a login when I attempt to login or register in any service. I've checked my saved passwords and autofill data, but I cannot find it, there's only usernames and passwords, and I have no saved autofill data, no phone number. Where can I look for it to remove it?

Just installed the latest 139 version on two computers, the system tray icon for unread messages appears in Windows 10, but not in Windows 11, and it isn't just 'hidden' as I have many icons hidden and just a few visible and have already checked that. Is the icon no longer part of the program?

I'm in the process of cleaning up Thunderbird e-mail before moving to a new computer. I started with 11,593 e-mails in my Inbox and 7,799 e-mails in my Sent folder. I'm now down to 7,634 in my Inbox and 4,965 in my Sent folder. I've allocated 2 weeks for this process and found that it's taking me about 3 hours per day to meet my daily goals. I'm finding that I'm spending at LEAST half the time responding to "Empty-Trash/Compact-folders" requests. There are times I can delete 50 e-mails at a time without getting a request. Other times I will try to delete ten e-mails and get the request. With the old version of Thunderbird I could literally delete hundreds of e-mails at a time. Can you help? Russ Bukwa Yardley, PA ps. I have intentionally given you specific numbers. Based on my software- and test-engineering experience, I speculate you need to create a stress test to solve this nagging problem.

Hello community :)

hope everybody is doing well. I´m coming here with with asking for a help.

I´m managing browsers (Google Chrome, MS Edge and Firefox) in my company via GPOs. What we´ve been dealing with since 135 version came up is having the "Did Not Connect: Potential Security Issue error page , Error insufficient cert transparency" while visiting our internal resources.

Despite of having the security.pki.certificate_transparency.disable_for_spki_hashes set up -> main three certificate hashes are correctly added, basically copying the setup from Chromium browsers , where everything works as expected , Firefox is not.

The only way how to make it work is via security.pki.certificate_transparency.disable_for_hosts , which is , of course, not desirable , because of the security risks.

Does anyone face the same issues ?

Thank you very much ya´ll

The Firefox version I used before was Mac version 136.0 After I updated to the latest version, I found that the fonts of the browser's tab bar, search box, and bookmarks became significantly larger. How can I change the font size?

I previously successfully imported my configuration from Thunderbird desktop to my mobile app by scanning a QR code, and it worked perfectly. However, I recently had to reinstall my computer's operating system, which resulted in losing all my Thunderbird data. Now I'm trying to export the configuration from my mobile Thunderbird app back to the desktop version, but the export process generates a file with a .k9s extension. My question is: How can I import this .k9s file into my desktop Thunderbird installation? Any guidance on this would be greatly appreciated. Thank you!

We are trying to create an out-of-office response email and have found an issue. When creating the filter to respond with, the "Reply with template" option under "Perform these actions" is missing. We have checked the usual reasons why, but we cannot find what the problem is. We are using an Imap account. We have the 139.0.2 version of thunderbird, and we have set up the template necessary for the response without any issues. What could be the solution?

I can access addons.thunderbird.net with Firefox without any problems or being asked to "verify you are human by completing the action below.", yet when I try to access it from Thunderbird's add-ons manager, I am asked to complete the captcha, which after about 30 seconds of "Verifying you are human. This may take a few seconds." goes back to "verify you are human by completing the action below." I tried troubleshoot mode to no avail, I am not using a VPN or anything like that.

Hello, I have a problem with one email account. Grouping does not affect it. It does not group... Everything was OK but I changed the POP server address to MAIL for a moment and then back to POP. Since then the account has not grouped. I want to have all the mailboxes "received" together. What could be the reason that this one account does not group and it used to group?

I'm opted in to studies, but unable to toggle the switch to opt-out because it is "grayed out" (screenshot attached).

Cannot find any studies-related solution in existing community Q&A except for one that says to toggle the switch to opt out, which isn't an option for me.

Thanks in advance!

On various websites with embedded podcasts, when the file goes past 1h the volume 'slider' goes away and becomes a basic mute/unmute button. How can i force Firefox to always display the volume slider?

Mozilla's documentation on IMAP Synchronization Mozilla's documentation on IMAP Synchronization indicates

"Non-synchronized messages are still accessible within Thunderbird. The only difference is that rather than downloading the entire message, only the message "headers" are downloaded. (Message headers contain information like the sender, recipient(s), subject, etc - everything except the body of the message.) The message body is not downloaded until you click on the message in the message list"

Under what settings (e.g. Sync messages checked or unchecked) does this behavior apply?

Thanks.

I have 4 email accounts setup in Thunderbird. When I turn my laptop on and open the program all the email accounts automatically expand(open to show their folders). I then have scroll up thru all the accounts and folders to get back to the top account. If I don't shut down or reboot they will stay closed or go back to what state they were in when last closed. If I reboot or turn on pc again they all expand.

I shut down and boot many times a day when moving around the office or on calls. So it kinda annoys me and slows me down. I cant seem to find a setting that fixes this if it is even possible. I want them to stay closed till I open them.

When I receive some special html formatted email e.g. from ticket system like Zendesk they look like this: https://assets-prod.sumo.prod.webservices.mozgcp.net/media/uploads/images/2025-06-17-01-06-32-c4ca42.png

When I want to reply to the text stays at the blue colored background and the text would be hard to read and it looks ugly: https://assets-prod.sumo.prod.webservices.mozgcp.net/media/uploads/images/2025-06-17-01-06-37-c81e72.png

Unfortunately I can't change background color to blank or white in Tunderbird 139.0.2. In menu of reply window "Page colors and Background", "Use custom colors", "Background" I can set to #ffffff of course, click apply and ok, but that doesn't change it: https://assets-prod.sumo.prod.webservices.mozgcp.net/media/uploads/images/2025-06-17-01-06-42-eccbc8.png

I suppose it relies to the html formatting of the received email because on starting to write a complete new email it works. But that's very annoying that Thunderbird doesn't manage to change background colors on already formatted html body. Is this a bug or only poor source code and the programmer didn't have much motivation to write and robust code which could gather all html emails?

Could you check with this test email to test and reproduce? https://limewire.com/d/pqbEk#1idjNje6b2

Thanks a lot! I'd be very happy about your help.

I am struggling trying to get a consistent format in Thunderbird. First of all let me say that I am happy with the default use of paragraph style and if I want to have occasional single spacing I can use shift-enter instead of enter. Most queries on formatting seem to be about getting single spacing all the time. That is not my issue. That means that if I compose an email from scratch everything is just the way I want it, using the default settings. The problem arises when I reply to an email. The settings then seem to be ignored. For instance the line spacing can be fixed to single spacing whether I select paragraph or body text and no matter what I do I can't get it to follow the default behaviour. Also, I noticed that the font goes to "sans-serifArial" instead of the usual "Variable Width". In fact if I try to select "Variable Width" in the Format menu it is just ignored. How do I get the default composition settings when I reply to an incoming email?