Thunderbird Community Forum

Thunderbird version number: 148.0.1 Mail provider: Yahoo Client OS: Windows 10

The issue and steps I tried to resolve: On 1 Jan 2026 I switched from Outlook client on my Windows 10 PC to Thunderbird 146.0.1. I did not import any user data from Outlook but started with a clean install of TB for the new year. I use yahoo.com with POP3 as my email provider. Server Settings: Server Name "pop.mail.yahoo.com", port 995, SSL/TLS, OAuth2 Outgoing Server: Server Name "smtp.mail.yahoo.com", port 465, SSL/TLS, OAuth2

it all worked fine and I was very happy with the setup. Then from early to mid-February I was unable to use my computer. When I finally accessed Thunderbird again, it connected to Yahoo and showed that approximately 800 email messages would be downloaded and started downloading them. After downloading about 100 messages, Thunderbird timed out and I haven't been able to get it to work since.

I have read and followed or tried to follow these articles plus others that I may have forgotten about (not listed in any particular order) - OAuth2 Authentication for Yahoo, AOL and ATT | Thunderbird Help - including all the steps in Please check the following before asking for support - POP access settings and instructions for Yahoo Mail | Yahoo Help - Automatic Account Configuration | Thunderbird Help - Manual Account Configuration | Thunderbird Help - Thunderbird and Yahoo | Thunderbird Help - Send and receive messages in Thunderbird | Thunderbird Help - Can no longer get emails | Thunderbird Support Forum | Mozilla Support - Emails suddenly stopped downloading to Thunderbird 140.2.1esr | Thunderbird Support Forum - Get Messages | Thunderbird Support Forum | Mozilla Support - Cannot receive messages | Thunderbird Help - Problem with Thunderbird working with Yahoo Mail acccounts. | Thunderbird Support Forum

I have removed all messages from the Yahoo inbox and tried to find one or more messages that may be affecting the download. I don't know the best way to determine that.

I use Windows Defender for my antivirus. I don't see anything in Defender that blocks or scans email messages which would prevent downloads, although I could be wrong about that. if this might be the issue, please provide some guidance about how to check Defender.

I have uninstalled and re-installed Thunderbird. In the process I downloaded the setup file for Thunderbird Setup 148.0 and installed that version. It later auto-updated to 148.0.1. Before installation, I removed all external connections from my Yahoo account and completely removed Thunderbird from my PC, including the profile and profile.ini. When I reinstall and switch the account to POP3, Thunderbird captures the App password from Yahoo and connects just fine. But it still times out while attempting the first download of a message. The first several times it timed out, an error message was displayed but now it doesn't show anything. Except no messages are downloaded.

At this point, I don't know what else to try. Since I don't have much experience with Thunderbird, I don't know how to troubleshoot the process (logs to look at, etc.). I don't want to go back to Outlook but I need the email client to work and download messages. Any help would be much appreciated.

I am running Thunderbird 140.8.1esr on macOS Tahoe 26.3

I created an IMAP account in Thunderbird to replace a POP account

I want to copy the Thunderbird message filters from the POP account to the IMAP account

I read articles on Mozilla Support and these said to copy the msgFilterRules.dat file but I cannot find this file

How can I copy the message filters?

I get this error ALL THE TIME from TB. Sending of the message failed. The message could not be sent because connecting to Outgoing server (SMTP) smtp-mail.outlook.com failed. The server may be unavailable or is refusing SMTP connections. Please verify that your Outgoing server (SMTP) settings are correct and try again. Copilot says that TB is NOT recognizing my personal Outlook email account as a viable SMTP account. Been on line with Copilot for couple of hours without success. Does anyone at Mozilla have anything to offer me?

On my Linux machine, I exported the public key for an email address in Thunderbird 140.8.0esr (64-bit) into a file. I transferred the file to my Windows 11 machine via Warpinator.

On the Windows machine I am running Thunderbird 148.0.1 (64-bit). In Account settings>End-to-End encryption, I click Add Key>Import an existing OpenPGP key>Select File to import, and then I select the file.

I get an error message: Error! Failed to import file.

I'm surprised. I would think that going from one installation of Thunderbird to another would work this way. I am concerned that I won't be able to read incoming encrypted emails without the key working.

Can someone help me?

Thunderbird--All of my current year INBOX emails disappeared. I have tried repairing the folder, deleting INBOX.msf and restarting including in troubleshooting mode, reinstalled Thunderbird. None of these actions changed the situation. Is it possible to retrieve these messages?

The INBOX folder is much larger than the INBOX.msf folder, so I'm thinking the message info is in there?

I;m using Windows 10.

Good morning . . . I have recently switched from an old Windows 10 machine to a new macmini, and have switched my Office 365 account over to it. Simply stated, Outlook is not working, and I have no desire to continue with it. Will Thunderbird suit my needs? Will it allow me to import my old contacts and emails, both from my Windows machine and the new MacOutlook?

There is a folder in my Downloads folder ('~/Downloads') called 'thunderbird.tmp' Whenever I delete it it reappears whenever I open Thunderbird. How do I relocate this because I like to keep my Downloads folder neat? I have not found an option for this anywhere in settings on the app.

About 140.8 ESR. Use the internal spam filter or externals like Bogofilter or SpamAssasain? 2nd: RSS option (Blogs and Feeds) every so often downloads duplicate feeds - how to remove duplicates?? Last: Earlier versions Thunderbird can import Outlook Templates - anyone knows how??? Example: I want to send my mom a Mother's Day email with a nice background but the background does not have to be animated - how would I go about that? I have plenty of email templates from Outlook 95/XP - just not sure how to import and use.

A few days ago I lost all of my saved email messages, plus "sent" emails, and "deleted" emails. I had important information stored there for future use. I am hoping to be able to retrieve it. Any help would be appreciated. Thank you!

I have been using Thunderbird with two POP3 Hotmail accounts for some time and I am trying to set up a third account with exactly the same configuration. However, both the automatic and the manual configurations failed. The new account receives mail, but the outgoing smtp server config seems to have a problem. Sending messages times out or keeps prompting for a new password.

The Hotmail account has POP3 and IMAP enabled. Thunderbird is set to receive all cookies. I cleared history and cache after every attempt and also temporarily disabled the firewall.

Any suggestions about what the problem could be?

Dear Support Team,

I am writing to report an issue I am experiencing with Thunderbird. Every time I use Thunderbird, an attached error message keeps appearing. This problem is delaying my work and affecting my daily tasks.

I kindly request your assistance in checking and resolving this issue as soon as possible. Please let me know if you need any additional information or screenshots of the error message.

Your prompt support would be greatly appreciated.

Thank you

HI, Thunderbird for Mac no longer allows me to see emails more than 4 months old. I have an AOL account and when I use the (lousy) AOL app I can see email going back at least a decade, so I know they are there.

This changed with a recent TBird update. I have checked online support, studied the different settings, and cannot find out how to set TBird to let me access all my email.

Can someone help me with this?

Thank you, James

Hey, everyone!

I'm having a problem with my Google calendar on on of my Macs.

O have an M1 Mac Mini and I can access all of my calendars through that system. However, I also have a 2013 MacBook Air running Big Sur 11.17.10 and I can only access two out of my four calendars via Thunderbird 128.14.0esr on that machine.

The four calendars I have subscribed to are my personal calendar, US Holidays, Stardates (because I'm a Trek fan) and Phases of the Moon. On my MacBook, I can only access or view my personal and US Holidays calendars. The other two can't be found by Provider for Google Calendar.

Anyone know why this might be and how I ca fix it? Seems silly that an Provider wouldn't be able to access these calendars since the same version functions on both TB 128 and TB 140.

Thanks!

On Bazzite, currently I'm running Thunderbird version 140.8.1esr.

I only have one account set up in Thunderbird, which is my iCloud email account. I followed the steps in this guide to set up my iCloud email account in Thunderbird, and it went very smooth.

No matter what I do, no matter how many times I mark all folders as read, the icon in my dock ALWAYS displays a new mail notification.

I've removed and re-added my account twice, and have uninstalled and re-installed Thunderbird from the Bazaar store. iCloud on the web also does not show that I have any new messages.

Today I have experienced a problem downloading new messages, bulk, trash or anything else in my mail server into thunderbird. it requires my primary password and then my regular password. I just set up my primary password so I understand why it is asking for that, but I don't understand why it is also asking for my regular password before I can get access to the mail server that I am using. the regular password was set up on 6/17/24 and until today it was working fine.

I have several emails (personal and business) that I use and have them grouped in Unified inbox. Recently one of those emails showed up as a new folder (just under Trash folder) in bold type. It has with a varying number of emails in it, now 18. When I click on the 'open folder arrow', a subfolder 'Archives' with nothing in it shows up. When I open the email folder a new page appears with the email as a header and underneath 'set up another account', 'import from another program', 'about mozilla thunderbird', and 'resources'. What is happening? How can I get rid of this folder since I can't read any of the emails in it and it is just a duplicate of the folder that already is working find in the inbox? TIA

I have been using Thunderbird for ages now with no problem, but I suddenly realised that no recent emails were appearing from my Gmail account. I have tried everything suggested on line to resolve the problem, including uninstalling and reinstalling Thunderbird, and deleting and re-entering my acccount details but neither the IMAP or SMTP servers will connect to Gmail. I have reset all of the server settings on Thunderbird, and have checked that Gmail is IMAP compliant (which, apparently, is is now automatically). I have spent hours trying to sort this out and am just at the point of abandoning Thunderbird completely, but I am loathe to do so if there is a solution. The latest error message i have received is "Unable to log in at server. Probably wrong configuration, username or password" but I don't know what else I can check or change.

I've been trying to move my Thunderbird data (148.0) from a Win10 to a Win11 machine. I've meticulously followed both the methods outlined at http://mzl.la/1ApHiU3. I have copied my original profiles.ini from the ...AppData\Roaming folder to that location on the new machine, then corrected the drive locations in the file (see attached profiles.ini image). (yes, the correct "j4sqsccb.XXXXXXX" folder is copied to the new installation's root: a bulky several-GB)

In order to try to replicate my original computer's admittedly-awkward installation from long ago, I have added the suffix " -p -no-remote" to the desktop icon's Target field. And on startup, the new T-bird does properly show my original profiles in the Select panel - even though I only ever used the one that functioned correctly, identified as 1 in the profiles.ini file (see Choose User Profile image, IDs X'ed-out).

However, on selecting that profile on the Win11 machine, Thunderbird just takes me to the account setup screen, as if it's unable to locate or load the account settings for that profile.

I'm only doing this clunky method of copying-over out of ignorance; I'd be very happy to simplify the mess I'd created decades ago with my original installation. OR if you think I'm better off wiping all evidence of past installations to start from a clean install, I'll be happy to do that. Please let me know if you need additional info I've failed to provide here!

Also adding images of my ...Roaming\Thunderbird\Profiles folder and Installs.ini file, just in case!