Thunderbird Community Forum

It's been almost a week now, and my 2 Microsoft email accounts will not connect to Thunderbird anymore. All was fine for years, but something changed that I can't figure out!?! I have gone to my Microsoft email server and checked that my passwords still work. I even updated one and it works on Microsoft server but not Thunderbird's!?!? I even deleted one email account from Thunder bird to re-install it, but when I tried a fresh re-install Thunderbird still won't connect to Microsoft server??? I'm at my wits end, and may abandon Thunderbird completely if someone there doesn't help me connect!!!

I apologize for the subject line, but there is no better way to describe the problem....

I've been using Thunderbird for a few months now and it has mostly worked well. Then this afternoon I was reading my mail in the Unified Inbox and I noticed something very odd. I had a number of emails showing in the header list with the same "From" and various subject lines. On the face of it, that wouldn't describe any weird behavior except that I noticed the subject lines absolutely didn't match the "From" information.

As I would go to read these emails, the email itself would be correct in the preview pane -- including showing the correct sender name and email -- but the "From" information in the header list pane would still be wrong.

I'm sorry that I can't post a screenshot to make this more clear because there is just too much personal information on screen. But these emails are from several different senders, received by several different email accounts. Everything is correct except that the "From" shown in the header pane is wrong. This is very obvious to me because I normally run entirely in the Unified Inbox with the emails sorted by the "From" information

One example is an email that is actually from "U.S. Department of Veterans Affairs <do-not-reply@notifications.va.gov>" which Thunderbird displays correctly in the preview pane (where I usually read my emails) and if I open the email itself, but the header pane says this email is From "Prepper-co <joshua@prepper-co.com>"

Another example is an email that is actually from "USPS Customer Support <uspscustomersupport@usps.gov>" but the header pane says it is from "Rainier Arms

These two examples were received in different email accounts that aren't even on the same server. I have other emails from these same senders that are shown correctly

I found this problem while using 150.0 (64-bit), which said 150.0.1 was available, so I restarted Thunderbird and it updated to 150.0.1 (64-bit) but the problem is the same.

I was a Thunderbird user for a long time, and so signed up for monthly donations in support. But I ended Thunderbird use when switching to a new computer, and now I'd like to cease that monthly automatic billing. But the Donor Portal doesn't work - the login link is never sent. So how do I terminate this monthly billing?

I have tried numerous times to enter an account into thunderbird with a password fail notification each time. It is the correct password as it works on my other mail accounts. also the correct email account is entered with the correct spelling etc. There is also a box beneath the password that says "log in" I have no idea what they mean by this. I have not encountered this before. I am using an HP Omni Book Ultra 14inch. running Windows 11. I have installed Thunderbird on several other devices without this problem.

I have a number of pop3 accounts with the same mail host, but suddenly one of them gives me the message "Unable to write the email to the mailbox. Make sure the file system allows you write privileges, and you have enough disk space to copy the mailbox."

I use Thunderbird on two Windows machines, and the problem is on both, so it is something in the interaction with the server, however, there is no problem accessing the mail via webmail directly on the server.

I have tried to change password on the account, but the problem did not go away. In fact, I got the box to tell me that the old password did no longer work, so I know that the problem pops up after log in to the account. Before the error message appears, the message "downloading 208 messages" (or something similar) briefly appears.

Is there a way to find out exactly what fails?

After tried many suggested steps to trouble shooting the problems, it still can't download Comcast emails. It keeps pop up "enter password" or "password failed" again and again. But I can send emails. I can't upload the trouble shooting information file to send. Thanks

Every so often I get an error message "Your message was sent but a copy was not placed in your sent folder (Sent) due to network or file access errors." I understand these if I am sending multiple large attachments as I am using Imap and the Sent folder is on the server. But I got it today with a simple pdf attachment. Is there anything I can do to alleviate this problem ?

Edition Windows 10 Home Version 22H2 Installed on 6/26/2024 OS Build 19045.6466

Thunderbird 140.10.1esr (64-bit)

OK, so I see where others Thunderbird users have previously asked about why e-mails are disappearing from their Thunderbird junk folder but have a quite different problem. So, when I go to my junk folder momentarily all the mails are present, but then right before my eyes 2 or 3 just simply disappear! They truly disappear and are nowhere in any folder on Thunderbird account -trash, archives, sent, etc. I did the obvious and Googled and there are some informative posts about Thunderbird settings for time-outs and filters and automatic deletion - BUT, BIG BUT all my settings conform already to all their suggestions on these various web posts. So at my wits end I ask the folks in the community if they have any explanation as to why e-mails in junk folder on Thunderbird literally just disappear in front of me. I would be greatly appreciative of any suggestions.

Hi,

I use the quick filter option very often. I use this to filter my message list by sender I'm a bit "tired" of constantly copying the sender e-mail address -> then pasting it into the quick filter field.

I am looking for an option like "Quick filter by this sender" or something like that Does anyone know how i can achieve this?

Some years ago there was an excellent extension from trusted contributor alta8888 called TotalQuickFilter (https://bitbucket.org/alta8888/totalquickfilter/wiki/Home) but unfortunately it was discontinued

I have a Postfix/Dovecot server that hosts 10 of my domains from one IP.

When you open Thunderbird, it checks the domains you have preset. I have two. This happens immediately, especially if there is no new mail on the server. Everything works fine.

If you have other domain mailboxes open, and I have eight more, and you click the inbox on each one, Thunderbird stalls at the fifth mailbox, regardless of the inboxes' selected order.

tail -f /var/log/mail.log - confirms this.

I have reset or modified everything I can think of. My server is not throttling Dovecot.

This must be something internal to Thunderbird, possibly related to only using a specific mail server IP for all domains.

Google AI suggests assigning a unique local IP alias to each domain on my server so Thunderbird thinks it’s talking to 10 different machines. This seems extreme.

Any solutions?

Every time I launch Thunderbird Beta 151.0b1 on Arch Linux, I immediately get a notification saying "The certificate for imap.gmail.com does not come from a trusted source." If I click through to the exception dialog, it shows "No Information Available / Unable to obtain identification status for this site" — it can't even fetch the certificate to show me what's wrong with it. The error only appears on launch and doesn't come back. Mail sends and receives fine.

From the terminal, openssl connects to imap.gmail.com:993 without any issue (Verify return code: 0, TLS 1.3, X25519MLKEM768). No antivirus, no VPN, no TLS-intercepting software. NSS 3.123.

Has anyone else seen this? Is this a known Beta issue?

Since yesterday (27 Apr 2026) any and all mail that comes into Thunderbird gets marked as SPAM. I searched online and found people saying that I could reset the junk training filter, so I did this, but incoming mail was still marked as spam. The next suggestion was to delete the training.dat file. Did that, restarted Thunderbird and incoming messages are still marked as spam. The last suggestion was to turn off adaptive junk mail controls. Didn't want to do that because I assumed that it would let spam through. Nope. Turned it off, restarted Thunderbird and two emails from my work came in and got flagged.

I'm running version 140.10.0esr (64-bit) on Windows 11. I am using IMAP to connect to the mail server but it's not running any spam detection software (like Spamassassin). I know this because it's my server and even if it was, no updates have been preformed since the first of this month and this just started happening yesterday. Combine this with the bug that Thunderbird notifies me of incoming mail, even if it's spam (didn't post about this because there are plenty going back a couple of years), is starting to make me look for an alternative.

How do I view the messages referenced by the dialogue asking me "Do you want to send your unsent messages now?" This dialogue suddenly started to appear when I startup Thunderbird. The dialogue has two buttons: "Send Now" and "Later." Thanks

Hello,

I want to use TB to access my GMX CalDAV calendar. Basically, this works fine. But completed Todos disappear from the list after a day or so ("Show completed tasks" is checked). If I export the whole calendar to a ICS file, the todos are included though.

Is this a bug or is there a configuration where I can change that behaviour?

Thanks for any help, Markus

I am using Thunderbird on a Macbook Pro 13-inch mid-2012, in a POP3 account

Thunderbird 140.10 is generally running fine, except that some sub-folders are not visible in my Thunderbird email tool view. I have a hierarchical

I have tried repairing the parent folders, but that had no effect.

The corresponding .sbd files are clearly visible in ~/<user>/Library>/<profile>/Mail/Local Folders/pop-server.<account> and being backed up in Time Machine backups.

Curiously, there is a much-truncated replica of some .sbd folders in Local Folders named /<folder-name>.sbd, all dated in 2013, yet the folder was created in 2017. I presume these refer to an update of Thunderbird that left some trash, and of no consequence. These are parallel to Archives and Archives.msf files.

Please advise on how to disambiguate this structure and recover views of existing mail folders not being displayed.