Thunderbird Community Forum

I made a folder and called it April. One day the folder just disappeared. No one seems to help me recover the folder and i need it. Once I moved emails into that folder they are no longer available in my inbox. SO if you know how to recover my folder help, or if you know how to recover emails that were sent to a folder, that would work also. I use Windows 11 and I have the most recent release of Thunderbird. I use Charter.net as my isp which is pop. Thanks,Charles

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?

For some reason I have lost all old emails in my inbox. I am only getting new messages, but I have many Thats I leaving in my inbox to address later. Please help me to recover them. This hspppen on or about a March 4, 2026

J'ai déjà un mail gmx , "andre.et@gmx.fr" est-ce cette adresse qui est crypter ?

Ou est ce une nouvelle adresse ? Chez Mozilla

Merci de m'éclairer André

I have Version 140.8.0esr | Released February 24, 2026, for Linux Mint (up to date)

I have a CardDAV address book on a Nextcloud instance that i want to sync to Thunderbird.

When i open Address Book and the clikc on " Create a new address book" the Account Hub modal window opens. None of the 4 options (including Add Remote Address Book" do anything, i.e. I can click as much as I like but nothing happens.

I cannot send from an Office365 account but can get mail - it simply says 'sending' but nothing happens.

I am using Owl (paid subscription) for my Office365 account.

I also have another email that is a simple IMAP account and that works beautifully!

I have a few folders I need deleting.

They do not appear in my webmail (mailserver) but do in Thunderbird - I have tried so many methods on your forums, but nothing is working - can you help?

Hi all — I’m running into a persistent threading issue in Thunderbird (v.148) vthat survives profile rebuilds and affects only specific conversations.

Symptoms Some threads show the expand/collapse carrot normally.

Other threads (same accounts, same folders, same time period) do not show the carrot.

The pattern is consistent: the same conversations fail before and after a full profile rebuild.

Both Inbox and Sent show a mix of threaded and unthreaded conversations.

No global setting seems to be wrong, because most threads work correctly.

What I’ve already checked mail.strict_threading = false

mail.thread_without_re = true

View → Sort By → Threaded

View → Threads → All

Folder Repair on Inbox and Sent

Full profile rebuild

Re‑added all accounts

Rebuilt .msf files

Verified that threading works across folders (Inbox ↔ Sent)

Verified that threading works across accounts

Verified that threading works for most conversations

Header checks For the conversations that do thread, headers look normal.

For the conversations that don’t thread, the headers also appear normal:

Message-ID: present

In-Reply-To: present

References: present

No obvious corruption, malformed IDs, or missing brackets.

What I’m trying to understand Why would Thunderbird:

Successfully thread most conversations

Fail to thread specific conversations

Preserve the same failures before and after a rebuild

Show carrots in Inbox but not in Sent for the same conversation

Show no global misconfiguration

Is there a known edge case where Thunderbird rejects a thread even when the headers appear correct?

Are there hidden rules about ambiguous References: chains, multi‑server storage, or cross‑account BCC workflows that could cause this?

Any insight into how Thunderbird decides not to show a carrot would be appreciated.

Thanks in advance.

I have some more email accounts with Hotmail and Outlook but there is popping an error just after the popup where it asks for permissions to connect Thunderbird to my account, and I say Yes and also receive the email that some new apps have connected to my accounts, but Thunderbird just at that step instead of Finish it displays that error message like asking again for Username and Password and even if I fill there the correct details it doesn't go further. Something is unclear at that step, because I also tried removing the passkey from the respective account Page at outlook.com and also the 2FA but the same.

Can you help me?

Thanks

Hello, so I have Thunderbird installed on 2 Windows 11 PC's both are updated and operating with all updates! On my 1st (main) PC which I use 98% of the time Thunderbird has been running perfectly with IMAP and Oath2.

Last night on the 2nd PC I rarely use I opened Thunderbird and it started to download messages for awhile and all my 2026 up until OCT 2025 disappeared?

I logged into Yahoo Mail from a browser and yup all gone?

I sent a deleted by accident request to YAHOO and today all my mail had returned when I checked on my 1st (main) PC.

I started the 2nd PC and all was good, till it started downloaded messages again? And POOF right back to square one?

What's happening? Should I confirm that IMAP and OATH2 are enabled on that PC before I do something else? I've sent another DELETED request to Yahoo and at this point I'm thinking to just REMOVE Thunderbird all together on the 2nd PC.

Does TB have a "complication" that I can put on my watch face? Most modern watch faces have slots for data provided by app developers like number of pending messages. Does TB have a complication for watch faces.

I want to send photographs from my Android phone to the "pictures" section of the Thunderbird e-mail program. The photos are going into that section but I can't see the picture itself as they just show wording as extensions. How do I get the actual picture to show up? How do I put my desired description of each of the "pictures" on the list along with the extension wording?

After updating Thunderbird to version 148.0 (64-bit), my system crashed. I rebooted and tried updating again. I am now sending and receiving emails normally from only one of my three AOL email addresses. I have attempted to reconfigure the settings on the other two manually, to no avail. Can the settings be corrected automatically? Please direct me to helpful guidelines that I could follow. Thank you.

I have a Windows 11 operating system. I tried browsing/uploading a couple email messages describing providing more information but wasn't successful. Can you help me ?

I am experiencing a persistent "ghosting" issue where deleted messages reappear in the "All Mail" folder. Environment: Mac Mini M2, macOS 15.2, Thunderbird 140.7ESR. Configuration: Gmail IMAP with "Auto-Expunge OFF" and "Immediately delete the message forever" selected in Gmail Web settings. Behavior: Using Shift+Delete or emptying the Trash in Thunderbird appears to work locally, but upon restart/re-index, messages return to the "All Mail" folder. Even after 2+ days, a search on the Gmail web interface still reveals the "deleted" items. Issue: The EXPUNGE command does not seem to be successfully committing to the Gmail server in this specific version build. Note that the TB has gone through some major rebuilds from 140.6 back to 128 ESR to 140.7ESR in the period from early Jan till 2 weeks ago. Very recently, TB became once again very slow on a start up, including after rebuilding of the large All Mail file of 66K items. A month ago, I added Satechi with 2TB drive split evenly between Time Machine and Other data. Significant oscillations took place in free memory on the MacHD between 60BG and 10 GB, currently at 58GB. Safari is my browser.

Four accounts: Rogers Yahoo, Office365, GMX, and a second Yahoo account

When Thunderbird recently asked to access to my provider's server, I gave my Rogers Yahoo account and password; everything looked fine. But when I tried to use my second Yahoo email account, all the folders contained the same data as the Rogers Yahoo account, even though the email addresses were different; my original emails were gone from the Inbox and other folders.

So I began to follow the instructions in Mozilla's page "OAuth2 Authentication for Yahoo, AOL and ATT". 1) with Config Editor, changed "mailnews.oauth.usePrivateBrowser" to TRUE 2) checked for "Accept cookies from sites" in Privacy & Security settings 3) checked authentication settings: All Outgoing servers were set to "OAuth2", as well as Yahoo and Office365 incoming servers. The GMX incoming server was set at "Normal Password" with no option for "OAuth2". 4) I am in Canada and do not use VPN. 5) Finally, I deleted the second Yahoo account (tc2002ca) and all its data from Thunderbird. I logged into Yahoo! Mail online to make sure I had the correct password. I then added tc2002ca as a new account using manual configuration. I entered all the settings to match the Rogers Yahoo account, except (of course) the password which was associated with the tc2002ca account. The result: same as before - all the folders of this account were identical to the Rogers Yahoo account.

To summarize, all the settings in the two Yahoo accounts were the same (imap.mail.yahoo.com and smtp.mail.yahoo.com) except the passwords. When I "tested connection to server" in each case it came back "Successful". Please help me get back to having two Yahoo accounts in Thunderbird, as I have had for years. By the way, I have had no problem using SeaMonkey in a similar way. Thanks!

I am using Thunderbird 140.8.0esr (64-bit) on Kubuntu 25.10 multi-monitor configuration. New install, very little customization.

Thunderbird will not retain the window size or position for the main window or messages. I have have tried deleting both the xulstore.json and session.json files (one at a time and both). When I delete the xulstore.json file and restart Thurderbird, it starts maximized. When I set the position manually e.g. to use about 90% of the screen for the main window and about half the width and about 90% of height for a message window and then close Thurderbird I can see the new window size vales written into xulstore.json e.g 2493 x 1362 and 1501 x 1317 "messengerWindow":{"sizemode":"normal","screenX":"0","screenY":"0","width":"2493","height":"1362"} "messengerWindow":{"sizemode":"normal","screenX":"0","screenY":"0","width":"1501","height":"1317"}

When I close and restart thunderbird it reverts to opening in the center of the primary monitor at a smaller size than when I closed it. The values in xulstore.json have changed to 960 x 540 "messengerWindow":{"sizemode":"normal","screenX":"0","screenY":"0","width":"960","height":"540"} "messengerWindow":{"sizemode":"normal","screenX":"0","screenY":"0","width":"960","height":"540"}

I found a similar recent question if this helps with a possible solution: https://support.mozilla.org/en-US/questions/1527783 but I cannot locate the referenced userChrome.css file to see if there might be something similar to try.

I am also using a multi-monitor setup. If I move the Thunderbird window to the second screen and close it, it always re-opens on the primary display at the 940x540 size. Thanks!