Thunderbird Community Forum

I just installed the latest Thunderbird 146.0 Win 11.

Configured my server data and Spam settings, etc. Mail coming in and going out OK.

Now I see some messages in the Spam filter that are not Spam. So I click on "Not Spam" button, and the message goes into my Inbox. Great. But after 3-4 seconds, the message is thrown back into the Spam box. I've told it 10 times "Not Spam" and each time it gets moved to the Inbox. Then 3-4 sec later it gets thrown back to the Spam box.

What am I doing wrong? Am I missing a setting?

Hi, I have thunderbird connected to a number of client corporate Office 365 systems (5 in total). The teams option works fine for 4 of them and is quite usable for chat but one of them responds that the browser is an unsupported version. I use Ubuntu 24.04 and have thunderbird and firefox installed from deb files (and the repos) so both are the current/release versions and overall everything works well so I don't believe there is a systemic issue. All connections to the clients' exchange systems are through the owl plugin. With the one client, as soon as you try to connect to their teams site, the 'Hmmm, your browser isn't supported' page comes up. As I manage that client's office platform, I know I've not made any changes to the back-end settings nor have I done so or had to do so on any of my other clients platforms so I don't think there is anything unusual about the Office 365 side (but am willing to be proved wrong). If I try logging in to the problematic teams site using firefox it works perfectly so I don't believe it is firefox being an issue. I have deleted and re-added the account. Has anyone else seen this and got it sorted, and if so how please? Many thanks, Scott...

I think I understand the difference between "folders" and Gmail "labels". So, I'm curious. When Thunderbird synchronizes with Gmail, does it create local physical folders for each of the Gmail labels in use, or does it use the Gmail label scheme locally? If a message in Gmail has two different labels attached to it, are there actually two copies of the message created locally in separate folders or not?

I am using 140.6.0esr (64-bit) and Windows 10. My Inbox disappeared. I was in it with no problems. Then I noticed two problems. I couldn't open new emails. It said connecting to server or loading content but email was blank. Also when I sent an email it could not copy to my sent folder due to network or file access errors. I could open and read all the other emails in my Inbox, just not three new ones. So I selected Inbox properties and repair. After the repair, my inbox is completely empty. It had thousands of messages. When I do a search for common emails I know were in my inbox, it only shows emails from subfolders. When I go to Inbox properties, it says number of messages: 0

Is there any chance I could talk with someone? Or that someone would call me? I'm not experienced in Thunderbird or email settings. And I don't like having to do it online. Richard Higgins Concord Mass

When I click on an email, instead of just showing the email, it sets up a Reply screen showing From me and To Me. At the bottom there is an alert: "A unique identity matching the From address was not found. The message will be sent using the current From field and settings from identity......" (lists my email user name and address). Im not clicking Reply, I'm just double clicking the message to Read it.

Running Sequoia 15.7.2 on MacBook Air. It just started today. I have turned it off and on, no change.

When I open the Thunderbird desktop app we receive this popup error message:

"Unable to establish TLS connection to POP3 server. The server may be down or may be incorrectly configured. Please verify the correct configuration in the Server Settings for your mail server in the Account Settings window and try again."

I have not found any configuration under the account settings to help with this, but if anyone has any suggestions to walk me through this to establish a connection again that would be most appreciated.

Additionally, when I try to send an email I receive the message: "Login to server smtp.cybermesa.com with username centinela failed."

After closing the error message box I received another error message: "Sending of the message failed. The message could not be sent because the connection to Outgoing server (SMTP) smtp.cybermesa.com timed out. Try again."

Is our issue then with Cybermesa and not Thunderbird? Or Is something wrong with Thunderbird due to our initial error message we received? Any suggestions is much appreciated.

I am getting frustrated that I keep getting multiple folders with the same name. When I save my emails to a local drive I use ALL MAIL to save and retrieve. Now I don't even have the ALL MAIL folder! Vern

An elderly friend uses Thunderbird on her laptop, and up until recently it has been fine. Then it just sits there and doesn’t show any new emails, just kind of frozen. She can send emails but not receive them.. Previously another friend had downloaded BT software to act as an alternate to access her @btinternet.com emails…. Strangely she hadn’t received any emails for a few days…. I found that her emails were being auto forwarded to an unknown email. I disabled that and her emails arrived and were visible on the BT site. I downloaded the thunderbird app to her mobile and attempted to set her account up , with no luck.

Any suggestions. Should I delete the thunderbird stuff on both laptop and phone and re-install?

Thanks

Maybe a red herring: I was in the middle of doing a Documents folder backup when I decided to open Thunderbird for some reason. Got an Unable to Load Profile type of message. And my attempts at a fix seem to just send me further down a rabbit hole. I started out by renaming my profile.ini file, but I really didn't know what the heck I was doing and possibly caused more harm than good. Then I tried to find my profile file/folder itself, using the Thunderbird > Troubleshooting > Profile Folder path and doing an import from inside TBird but that ended up with various problems such as drilling down to the profile folder from within TBird but then when I clicked Select Folder in Thunderbird, that didn't trigger any sort of import.

I also spent a good deal of time trying to find my AppData folder, finally being able to view it (a hidden folder, apparently), and saw several recently-dated profile types of folders, but again, I couldn't manage to "hook up" any of those folder/files from starting inside TBird and selecting Import... I ended up just stuck inside a folder, not triggering any Importing activity.

Finally I found a profile folder (5yed...) at a higher level on my PC than inside that long AppData Roaming Thunderbird path. THIS profile was inside: D:\DOCS\Thunderbird\Profiles

Now THAT folder I managed to get an Import to trigger. But the result was an Error Message telling me to go find my Error Console. Can you please see the attached Error Code display screengrab and tell me there's hope that this was at least the right file but just poor results that I can fix somehow???

The following is my copy/paste of the text I see in the Error Console display that's in my screengrab after trying to import the above 5yed... profile, in case it helps you see it better:

1765349209272 addons.xpi WARN Checking C:\Program Files (x86)\Mozilla Thunderbird\distribution\extensions for addons WebGL context was lost. 2 Troubleshoot.sys.mjs:727:17 Content-Security-Policy: This site (https://www.mozilla.org) has a Report-Only policy without a report-uri directive nor a report-to directive. CSP will not block and cannot report violations of this policy. thunderbird downloadable font: Glyph bbox was incorrect (glyph ids 441 459 695) (font-family: "Open Sans" style:normal weight:700 stretch:100 src index:0) source: https://updates.thunderbird.net/media/fonts/opensans-bold.woff2 downloadable font: Glyph bbox was incorrect (glyph ids 459) (font-family: "Open Sans" style:normal weight:400 stretch:100 src index:0) source: https://updates.thunderbird.net/media/fonts/opensans-regular.woff2 Uncaught (in promise) NS_ERROR_FILE_NOT_FOUND: Component returned failure code: 0x80520012 (NS_ERROR_FILE_NOT_FOUND) [nsIFile.copyTo]

   _recursivelyCopyMsgFolder resource:///modules/ThunderbirdProfileImporter.sys.mjs:652
   _recursivelyCopyMsgFolder resource:///modules/ThunderbirdProfileImporter.sys.mjs:661
   _mergeLocalFolders resource:///modules/ThunderbirdProfileImporter.sys.mjs:634
   _importServersAndAccounts resource:///modules/ThunderbirdProfileImporter.sys.mjs:243

ThunderbirdProfileImporter.sys.mjs:652

Also attached below are also:

• a screengrab of a set of profiles I found, but when I drilled down to them from within TBird's Import selections and clicked Select Folder, as far as I got was an open folder, or something like that.
• Thunderbird's Troubleshooting Info "Profile Folder" path.
• Message telling me to see the Error Console. The message appeared right after I tried importing the profile that's stated in TBird's Troubleshooting Info "Profile Folder" path.

Here's the copy/paste of the Error Console message display after my try at importing the profile that is in the path that TBird's Troubleshooting Info page "Profile Folder" states (maybe it's the same as my 5yed...profile import try's Error Console display, dunno:

1765353636640 addons.xpi WARN Checking C:\Program Files (x86)\Mozilla Thunderbird\distribution\extensions for addons Content-Security-Policy: This site (https://www.mozilla.org) has a Report-Only policy without a report-uri directive nor a report-to directive. CSP will not block and cannot report violations of this policy. thunderbird WebGL context was lost. 2 Troubleshoot.sys.mjs:727:17 downloadable font: Glyph bbox was incorrect (glyph ids 441 459 695) (font-family: "Open Sans" style:normal weight:700 stretch:100 src index:0) source: https://updates.thunderbird.net/media/fonts/opensans-bold.woff2 downloadable font: Glyph bbox was incorrect (glyph ids 459) (font-family: "Open Sans" style:normal weight:400 stretch:100 src index:0) source: https://updates.thunderbird.net/media/fonts/opensans-regular.woff2 Uncaught (in promise) NS_ERROR_FILE_NOT_FOUND: Component returned failure code: 0x80520012 (NS_ERROR_FILE_NOT_FOUND) [nsIFile.copyTo]

   _recursivelyCopyMsgFolder resource:///modules/ThunderbirdProfileImporter.sys.mjs:652
   _recursivelyCopyMsgFolder resource:///modules/ThunderbirdProfileImporter.sys.mjs:661
   _mergeLocalFolders resource:///modules/ThunderbirdProfileImporter.sys.mjs:634
   _importServersAndAccounts resource:///modules/ThunderbirdProfileImporter.sys.mjs:243

ThunderbirdProfileImporter.sys.mjs:652

Thanks for any help in getting through this.

Been getting a bunch of this, usually in my TB TRASH folder, I think from the Outlook online server.

The server couldn't retrieve the following message:

Subject: "<Removed for PII>"

From: "Not available" ("Not available")

Sent date: 10/31/2024 2:25:02 PM

The message hasn't been deleted. You might be able to view it using either Outlook or Outlook Web App. You can also contact the sender to find out what the message says.

I have 2 personal email accounts: Outlook and Gmail. My client is Thunderbird. Running Win11 25H2. Far as I know, problem began recently. This is a screenshot of some messages from TBirds TRASH folder.

User's image (In images) Thunderbird just tried to fetch emails. Got a notification that it could not get messages, this time from GMail.

What does this mean? Outlook/Gmail servers or Thunderbird? What do I need to do?

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?

New laptop. Took it to the Geek Squad to move the data from my wife's old computer to new. They had me sign in to Windows on the new machine and perform the setup steps, then took it and the old computer to do the data transfer. The issue is that the returned new computer had my MS profile on it but my wife's mail under that profile.

To try to correct this, I set up my wife's profile on the new laptop and my thought was to export the email from my MS account's TB data to a public folder, turn off TB and sign off my MS profile, sign back on to my wife's MS profile, start TB and import the zip file in the public folder. However, it tells me the folder is too large and I must unzip and import from the extracted folder. Windows Explorer won't let me unzip the file saying it's not a valid zip file. Ideas?

Thanks!

I want Thunderbird to stop marking everything I delete as having been read. The way it works now, if I accidentally delete mail that I haven't read yet it's much more difficult to find it when everything is marked read even when it wasn't. I searched everywhere and haven't come up with a solution for this. It was reported as a bug years ago and was never fixed.

As it turns out, my LOCAL FOLDERS is a sub-file in my account. I have a whole bunch of sub-files within the LOCAL FOLDERS sub-file. When I right click on that file, it does not give me the option to reorganize (re-alphabetize) that sub-file. In other words, I want to reorganize the sub-files of a sub-file. Is this just not an option, or is there a way to do this?

I'm dealing with a properly updated 'bird: 140.5.0 (32-bit) running on an equally updated Windows 10 desktop. First thing this morning, out of nowhere, I started getting an "unable to write the email to the mailbox..." message when sending, thus I could send but not save. And then I realized I wasn't receiving either, on all three accounts in my Thunderbird. I stopped everything and focused on trying to fix this. It's been an all-day, losing effort. So far.

I tried the various quick checks and fixes recommended here and there: I'm running the program as an administrator. I restarted the program. I rebooted the computer. I think I have enough disk space, but to be sure I deleted some bloat from possibly overly large files. I compacted, even though the program is configured to do that regularly. I temporarily disabled my antivirus program. I went into my webmail and deleted all messages that have arrived since my Thunderbird stopped receiving, in case one of them was corrupted. And probably some other attempts as well. Nothing has helped.

And now a second, even worse issue has fallen from the sky. Thunderbird opens. The folder list is where it always has been. The number of unopened messages in each folder is there in boldface, as always, but...the folders are all blank and I get the dreaded popup: "unable to open the summary file...." Have I lost my years' worth of carefully curated emails?

I've tried folder repair. I've deleted parent.lock. Etc. Nothing. Nothing. Nothing.

I will be super-grateful for any wisdom sent my way.