Thunderbird Community Forum

Optus (Australia) emails can't be sent or received by Thunderbird on my PC via my Optus wifi internet connection. I can use emails on my phone via mobile data with wifi turned off (different email client on the phone, though). Optus checked all the settings on my PC with me and they are all correct. They insist that it is a Thunderbird issue (doubtful, IMHO) and that I contact you. Is there an issue with Thunderbird connecting with Optus email? If so. is there any resolution to the issue? If not, can you confirm no problem from your end so I can get back to them (again!)

I have a professional email address and a gmail address configured correctly in thunderbird. I also have a number of google calendars configured in lightning using the built-in google calendar support (i.e., I am not using the old google calendar plugin). Until recently, when I received and accepted a calendar invitation sent to my professional email address, thunderbird would ask to which calendar I wanted to save the invite. I would select the calendar I wanted and it would be saved appropriately.

A week ago, I created a new google calendar and added it to thunderbird/lightning using the built-in google calendar support. Now, when I accept a calendar invitation, it automatically goes to the new calendar (which is generally not appropriate) without asking me to choose. Furthermore, I am unable to edit these calendar events to change the calendar they are associated with. I have checked the properties of both the new and old calendars and they look the same.

The only seeming solution I found was to make the new calendar read only and disassociate it from an email address, and then undo both those options. For the time being, this operation seems to have gotten back the option to select which calendar invites are saved to. But I would still like to know if this was the correct solution and better understand how thunderbird chooses to save event invitations.

Hi there! I and my colleague encounter some bugs with Thunderbird and we would like to seek your advice in regards of the issue.

1. <user a@citizen-systems.com.hk> was supposed to get a cc copy of the email sent by <user b@citizen-systems.com.hk> at Mon, 12 Jan 2026 09:35:19 +0800 but it never reached. The receivers, namely <user c@systems.citizen.co.jp> and <user d@citizen-systems.com.hk>, however, were able to get the mail. <user d@citizen-systems.com.hk> and <user a@citizen-systems.com.hk> are working at the same office and under the same network. Network provider checked the protocol, router, traffic and firewall are working as normal.

2. <user e@citizen-systems.com.hk> found a number of emails that she kept at "Inbox" disappeared on 12 Jan 2026 morning +0800.

She is unable to find it anywhere at her whole mailbox but has to ask the senders to resend them to her.

It would be very much appreciated if you can check and advise how to prevent the issue from happening again.

(PII redacted by moderator)

Window 11 desktop. Just downloaded and installed Thunderbird. Unable to type anything in to Calendar . Can only create event and that is unable to pick a time of the day just ends up at the top

Some senders for example Tangle go straight to my trash and if I move them to the inbox it immediately moves it back to trash. I do not understand what is blocking this nor how to do anything about it. Some send such as Erick Erickson generally go to inbox, but not always. Sometimes it goes to trash again.

Same Topic slightly different question... when I tell Thunderbird to delete all messages older than one year it does not do it. I do not know how to solve this problem. I do contribute to Thunderbird and thank you very much for any help that you can give. Don

TB 140.7.0 32bit, Windows10 64bit

My email provider implements black-box spam processing, with deemed spam redirected into a "Spam" folder at the server end which by default is flushed every 60 days.

To view all the incoming mail, I now not only need to view the account Inbox as TB presents it, I also need to log in to the provider's Web interface to inspect the account's Spam folder. I'd rather view this Spam folder through the TB interface to avoid extra logins.

So I

(1) Created a Spam subfolder under Local Folders using the TB interface. The Properties function reports its path as mailbox://nobody@Local Folders/Spam (the Inbox path is reported as mailbox://nobody@Local Folders/Inbox). These paths are read-only as presented by the Properties function.

(2) Used the Config Editor to set mail.server.default.check_all_folders_for_new to TRUE.

(3) Restarted TB, verified that check_all_folders_for_new was indeed TRUE.

However, while the account's Spam folder was known to contain 2 entries at the server side, the end-user Spam folder was not populated, whether by way of TB restart or manual invocation of the Get All New Messages function.

Any ideas ?

Thanks.

Hi, So I used Thunderbird to create a zipped backup file of my profile. I got the warning that if the file size if more than 2 GB I may want to make a manual backup. I proceeded, and ended up with a file that was 15 GB. I then uninstalled Thunderbird, reinstalled it, and tried to import my backup file. Thunderbird gave an error, saying the file is too large, and I should manually extract it. Okay, I tried, but Windows 11 failed to extract the file. I then used a third-party app to extract the files. This gave me a c2140ucr.default folder that contained three direct subfolders and many, many files. I located my inbox.ca file, which is what I really want, but I cannot find a way to import it into Thunderbird using the Tools menu. Any ideas on how to recover my previous profile would be appreciated. Thanks.

Thunderbird has managed to keep all the message headers however the body of EVERY email is now empty. I had archives of email going back to the 80's and it's all gone. I tried to import backups again but TB throws away the body of the messages.

Note that there are many different email address formats in use from regular TCP/IP, XNS, UUCP, Mainframe 8.8, and others. The headers are there and show the addresses but the content is totally empty for every message.

Before TB gets a hold of them, I can read them so I know the data is there and it is TB that is removing it.

Please help

hello,

i am trying a second time to submit my question:

how can i migrate 3 months of prior thunderbird emails from a docked ssd to the ssd installed in my computer. please see attached photo.

the migration must be done without creating duplicate emails for the months of January 2025 through August 2025. more importantly, i don't want to disturb or lose the emails of December 2025 and January 2026 that are now on my computer. so my simplistic analysis is that i have to be able to move hand-selected emails from the docked SSD to the SSD installed in my computer. otherwise if i move an entire profile, it will erase my current profile that includes December and January emails.

thank you

I am running Thunderbird version 128.11.0esr (64 bits) on Windows 10 Pro. I have defined, in Windows, the default program for .doc and .docx files to be LibreOffice Writer and this works fine when I click on such a file in Windows.

But when I got a docx attachment in a Thunderbird email, and clicked on it, nothing happened. When I right-click on it, it just offers to open (not to select which program to open it with). I have to save the file locally, and click on it in Windows in order to open it.

This is very frustrating, all the more so that it used to work. I tried adding the two following lines to the prefs.js file, to no avail - no change:

user_pref("network.mime-handler.external.application/vnd.openxmlformats-officedocument.wordprocessingml.document", "D:\\Program Files\\LibreOffice\\program\\swriter.exe"); user_pref("network.mime-handler.external.application/vnd.openxmlformats-officedocument.wordprocessingml.document.useSystemDefault", false);

Any suggestions? Thanks!

Hello:

I am unable to send email messages to any "@zianet.com" email accounts (New Mexico). I can receive Zianet email messages, but I cannot Send or Reply. Zianet says they recognize the Earthlink IP Address, but that there is a third sender's IP Address they don't recognize. Earthlink says they have given Zianet the IP addresses. Does Mozilla Thunderbird have a third IP Address I can share with Zianet Tech Support? Zianet's phone number here in Las Cruces, New Mexico is: 1.575.353.1234. This issue is causing a lot of problems for me and my business. Thank you so much.

Here is the error message:

Delivery has failed to these recipients or distribution lists:

Server "zianet.com" returned an error:

* [hpollard@zianet.com]: message reached max retries

Authentication-Results: earthlink-vadesecure.net; auth=pass smtp.auth=jeanfulton@earthlink.net smtp.mailfrom=jeanfulton@earthlink.net; Received: from [192.168.10.102] ([67.143.180.56]) by vsel1nmtao01p.internal.vadesecure.com with ngmta id 48c82eca-188a1cab439a7dda; Mon, 12 Jan 2026 22:35:32 +0000 Message-ID: <35210bba-27ea-40e6-858d-5d16b6b6d300@earthlink.net>

In the upper right hand corner there should be a minus sign, restore/down sign and an X. Instead of these I have what looks like an X in a box. It appears to be fixed when I run in Trouble mode. Even the default theme shows it wrong. This just began happening. Thanks to anyone who can help me out.

If I begin typing while before I begin a new message, sometimes a message will disappear and I can never find it again. For example an "A" will move it to the archives. But whatever letter I press, the message disappears. It's not in archives and not in trash. How do I find it again?

I believe that version 145.0, newly installed on the 9th December, 2025 was showing server folders correctly; the server folder name matched the client folder name.

After upgrading to 146.0 on the 10th December, the server folder names for some folders are displaying with different client folder names.

The IMAP account has both "spam" and "junk" folders, Thunderbird is now displaying both as "Spam", you can only determine which folder is which by showing folder properties. It appears to users that there are two "Spam" folders now and not the two distinct folders with their own names.

Similar behaviour is happening for "Sent" and "Sent Messages" folders, both now display as "Sent".

These changes are confusing, the client sees two "Spam" folders and two "Sent" folders instead of the original proper server folder names.

Why has the display name for these folders changed?

How can I get TB to display the real underlying folder names?

Hello everybody. Since today or yesterday, my Thunderbird has stopped refreshing the list of messages. The number of new/unread messages in the Inbox and other folders is shown and updated right but the main window with the list of the messages does not get refreshed and only shows the last message from couple days ago.

I've tried to follow a bunch of guides and ideas (repairing folder, deleting .msf files...) and even removed the account and tried adding it again. The list of folders is right but now there are no messages at all. All folders look empty.

I've found out that in the folder on the disc where there are supposed to be the "INBOX.msf" and "INBOX" files, that the "INBOX" file without the file type is missing. And it's the same with every message folder, there are only .msf files on my PC where I removed and re-added the account. On my laptop, the "INBOX" file still exists but does not get updated.

This thing is happening with only one of my e-mail accounts, the others get updated fine and new messages are shown. It is IMAP server, imap.atlas.cz, Port 993, SSL/TLS with a password.

Can anyone help please?

Several days ago we inadvertently deleted batches of emails from our two Thunderbird Gmail accounts on our PC and Apple devices. The lost emails were duly recovered but only after having to change my Google password. However one of our Thunderbird Gmail account will not download any new messages coming in. Ultimately we deleted that account from Thunderbird, intending to reinstall it. We deleted the account by pressing the Red button in account settings. We confirmed that messages are received to Gmail's Web page Inbox Now when I attempt to reinstall the account and press Add Account, I get the UNABLE TO LOG IN AT SERVER MESSAGE shown below. The "Your Full Name" I am putting in is the name on the Google account deleted from Thunderbird, and the password I have tried is my new Google password. I have tried the process of not adding in the password until requested to do so but this did not work either. Any suggestions please?