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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.

How do I restore selected emails or folders from a backup made with Export? I only want to bring in 30 or so (which were accidentally deleted). I'm using a Windows 11 PC.

I'm nervous about reloading the backup because it was some time ago (and I *really* don't want it to download new emails).

Hello, I just enabled the backup sync option for the Firefox web browser (Win 10). What is the equivalent process, or recommended method of enabling a backup for mail folders, calendar entries, address books, settings, etc. of the most current Thunderbird version on a Win 10 PC? I could not find a clear answer in the help forums. Thank you.

Dear community members, Since receiving the Thurderbird release 140.4.0esr on Oct 14th, I have not been able to send email from any of my accounts (2xIMAP and 3xoffice365 through OWL). Nothing has changed in the account settings. Receive works ok. The usual easy fixes do not seem to work (restart, firewall switch-off, etc.). Any ideas beyond having to rewind to an earlier version and rebuild the whole thing (hopefully not!)?

Version 140.4.0esr Build ID 20251010020716 User Agent Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:140.0) Gecko/20100101 Thunderbird/140.4.0 OS Darwin 24.6.0 Darwin Kernel Version 24.6.0: Mon Jul 14 11:30:30 PDT 2025; root:xnu-11417.140.69~1/RELEASE_ARM64_T6020

Thank you for your help! Heli

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?

Hi, The question is in the title. I have imported my Outlook data in this 32-bits version (updated to 140.7) . I would like to keep them in a 64-bits version (147). I didn't find the solution. Thank you for helping me. Michael.

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, In a recent upgrade to Thunderbird Mac OS x146.0.1 (aarch64), the FILTER selection options on some drop down menus are now blank. Example: "Priority" "Status"

These drop down menus now show no options (eg. read,)

I've two screen shots to illustrate.

Thanks for looking into this.

Glenn S

I have just installed Thunderbird v146.0, set up the first mail account (POP3) OK, then tried to set up a GMail IMAP account. I inadvertently gave it the wrong password, so the Account hub throws out the connection with an Authentication error "Unable to log in at server. Probably wrong configuration, username or password".

The problem is I can see no way of amending the password; if I try and set up the account again, it just skips the "enter password" step, presumably because TB thinks it already knows the password for this email account. I have tried the following:

- The "edit configuration" feature in the account hub doesn't have a change password option - The Saved Passwords section in Settings > Privacy & Security doesn't show the Gmail creds, presumably because it failed to set up this account in the first place - I reinstalled TB, having previously deleted the Profiles folder in C:\Users\<username>\AppData\Local\Thunderbird; everything I've read on this suggests this is the one and only place where TB keeps its data. However, when re-entering TB, the POP3 account I set up is still there, so there must be somewhere else that TB is storing its data, I guess the Registry?

Am I missing something? I can't be the only person who has had this problem!

Thanks

It seems that after updating to the latest version, Thunderbird is not displaying new emails. The numbers of new emails in the folders are changing, but the emails are not loading. I performed maintenance on the folder, but the emails disappeared and I no longer have any emails in my Inbox. I use IMAP, everything is OK on my phone and on the web. This is happening with Thunderbird at home and at work.

Translated with DeepL.com (free version)

Hello, I've been happily using Thunderbird for a few years now. Since yesterday, I have been unable to send emails in Thunderbird, but I can receive them. I can send emails directly through my Skymesh Webmail, but in Thunderbird when I try to send an email, I get the following notification, even if I am sending it to only one recipient. Sending of the message failed. The message was not sent due to exceeding the allowed number of recipients. The server responded: Insufficient system storage. Please help. Regards, Judy Osborne 15th January 2026 [edited from public] @bordernet.com.au

In earlier versions, the calendar list button appeared in the left sidebar, so I could decide which calendars to display and change the default color. But I can't find this now. How can I change an existing calendar?

Thunderbird message header pane is so large that I can't read messages. The top 2/3rd of my screen has the list of messages, header bar, files, etc. The bottom 1/3 is for the actual email message, but the header takes up nearly half of that with just the "From", "To", and "Subject lines taking up more than half of that space. Depending on the text of the html message, sometimes I can only read one line at a time, which makes it difficult to actually comprehend a message while scrolling, particularly if it's a long message. I can't resize it to make it larger, though I can make it smaller. My eyesight isn't quite as good as it used to be so I use a larger font than I used to, ie: 12pt rather than 10pt, and that makes it worse. Any suggestions?

I get a notification that includes this message when I try setting up my outlook account and this prevents me from getting mail to my email in Thunderbird, not past or new emails show up and I can only view an empty inbox, contrasting my other emails which work perfectly fine.

When I try setting up my email It says my username or password is wrong when it isn't and when it input, and that I have to put in my login. I put my login in and it says my username and password are incorrect even though my login info is correct I don't know what's going on, the error info isn't very helpful.