Thunderbird Community Forum

Hello Thunderbird Support, I am experiencing a severe IMAP folder synchronization loop with my Yahoo Mail account (paulpersonne519@yahoo.fr) inside Thunderbird. Yahoo Support claims the issue is caused by Thunderbird's folder mapping, so I am reaching out to you for a solution.

1. 1. The Problem:

The system-protected folder "Bulk" (Spam) has somehow been moved or mapped as a subfolder inside the "Trash" folder.

• In the Yahoo Mail Web UI (Chrome), the subfolder is invisible, but the Trash directory shows an arrow (^) indicating a child folder exists.
• In Thunderbird, the Bulk folder is clearly visible inside the Trash folder, marked with the flame (Junk) icon.

1. 1. What goes wrong:

When I delete spam messages via Thunderbird, they get trapped inside this nested Trash/Bulk directory. If I try to delete or empty it, the emails disappear but the folder itself cannot be removed.

1. 1. Steps tried so far that failed:

  1. Attempting to delete or rename the Bulk folder inside Trash gives the server error: [CANNOT] DELETE failed - Mailbox is reserved.
  2. Using Shift + Delete on the folder is rejected by the Yahoo server.
  3. Unsubscribing from the folder via "Advanced IMAP settings" -> "Show only subscribed folders" fails; Thunderbird re-downloads the structure on the next sync.
  4. I have completely deleted my old Thunderbird profile folder and created a brand new one using thunderbird.exe -P. Upon adding the Yahoo account via OAuth2, Thunderbird immediately pulled the same broken Trash/Bulk structure from the server again.

Since Yahoo refuses to help and claims Thunderbird caused this mapping loop, is there a hidden config setting (about:config) or a database override in Thunderbird that can force the server to release or move this reserved folder back to the root directory? Thank you for your assistance.

My recollection is that prior to a recent automatic update to Thunderbird 140.12.1esr (64-bit) when I had a message composition window open, there were "SEND" button and possibly a "SEND LATER" button (to the left of the addressee and cc addresses in addition to the keyboard shortcuts (CTRL ENTER and CTRL SHIFT ENTER).

Following the update, there is no longer anything to the left of the addressee information. I have checked the toolbar menus, and there do not appear to be any button options. I can still send messages, but the lack of the buttons is a hindrance.

Hi - I am running Thunderbird release 140.12.1esr (aarch64) on a desktop Mac runnning Sequoia 15.7.3.

Thunderbird is set up to take addresses from my personal address book. When I bring up Collected Addresses in the Thunderbird address book, there are no email [or any other kind of] addresses listed. Absolutely nothing in Collected Addresses within the Thunderbird address book.

There are 21 email and other addresses listed in my Mac OSX address book. When I search my stored email messages, Thunderbird brings up each and every address that matches the string in my query. The matches appear to go back more than twenty years.

I have searched the web on how to clear the autocomplete cache. There appear to be several different methods. I have tried bringing up the matches via the string and the resulting query, and then scrolling through the matches with the down arrow key. When I reach an address I would like to remove from the autocomplete cache, I have tried clicking on various combinations of keys. These combinations include:

1) Shift + Delete keys 2) Option + Delete keys 3) Command + Delete keys 4) Option + Command + Delete keys 5) Just the Delete key

My intuition tells me the autocomplete cache must be stored somewhere in a file. I cannot conceive of the autocomplete cache being maintained across versions, hosts, etc. over a period spanning twenty years without getting stored in a file.

Please enlighten me on how to clear out the junk email addresses in my autocomplete cache.

Thanks in advance for your help.

Regards,

Corwin

Old PC died and will not start up. I bought a new PC and was able to recover most file in the initiating the new desktop. I installed Mozilla Thunderbird on the new PC, but when I opened it only 55 EMAILS were available with the oldest being about 2 weeks old dating back to July 16, 2026. Is there a time limit for maintaining EMAILS online? Also, all of my contacts and Calendar events are not available.

I had created several folders to save important EMAILS and none of those sub-folders are visible to me. How do I get to those folders and EMAILS? Contacts and calendar are not as important, but they were used all of the time to communicate and stay on schedule

I tried to import using the tool provided, but received the following message: Import failed unexpectedly, more information may be available in the error console.

I have lots of important information that I can't access!

Help

I have thunderbird installed on my PC, and my main email account is a gmail account. I download from gmail using POP protocol (SSL/TLS connection security, OAuth2 authentication). I have been using these settings for a long time (15 years?).

This afternoon, thunderbird stopped downloading my messages. No error messages : just "no new messages to download".

I can see (by logging directly into my gmail account using my browser) that there are new messages on the server. They're not spam or junk, and they're not getting downloaded into my (local) spam folder. They're not getting downloaded at all.

I still have room on the google server (it's about 87% full), and room on the hard drive on my computer (about 3 GB).

I recently upgraded to 140.12.1. When I attempt to run the Remove Duplicate add on it hangs.

I suspect this is something to do with an additional menu item that now lists under Remove Duplicates Saying "Set original message folder(s) for next duplicate search". However when I select this, I get an error message from Remove Duplicates saying "Invalid choice of original message folders."

I have no idea where to set the folders, nor what to set them to..Can anyone help - it's an excellent add on which I use a lot.

Quick Filter does not return correct results in Unified Inbox (Thunderbird 140.12.0 ESR)

I'm using Thunderbird **140.12.0 ESR (aarch64)** and believe I've found an issue with the Quick Filter when searching the **Unified Inbox**.

• • Steps to reproduce:**

1. Open the **Unified Inbox**. 2. Open the Quick Filter bar. 3. Enter a search term (e.g. "maddy").

• • Observed behaviour in the Unified Inbox:**

• With no "Filter messages by" options selected, entering a search term does not filter the message list.
• Selecting **Sender**, **Recipients** and **Subject** still does not return the expected email.
• Selecting **Body** changes the results after a delay, but the expected email is still **not** returned.

If I open the **actual Inbox** containing that same email and repeat the search:

• The expected email is found using **Sender**, **Recipients** and **Subject**.
• When **Body** is selected, the search takes longer and eventually returns additional matching messages, including the expected email.

This behaviour is reproducible with multiple search terms and suggests that the Quick Filter does not search the **Unified Inbox (virtual folder)** correctly, even though the same search works in the underlying physical folder.

Could you please confirm whether this is a known issue or a bug?

On Saturday morning 27 June 2026 I tried to login my Orcon email account via Thunderbird (which I have been using for a long time). But my login didn't work, I got a message saying "login to POP3.orcon.net.nz with username habitation failed." On 30th June 2026 I reported the problem to Orcon.

Orcon gave me the following settings for Thunderbird. I have done that and even made a new account: Incoming Server Type: IMAP Mail Server: imap.orcon.net.nz Port: 143 SSL: Off Authentication: On (username and password required)

Outgoing SMTP Server: Mail Server: smtp.orcon.net.nz Port: 25 SSL: Off Authentication: Off

Since then I have spent many hours and going around in circles with Orcon's Technical Support to resolve this, but no luck. They blame Thunderbird. I used Thunderbird Troubleshoot Mode. The message that comes up reads: login to server mail orcon.net.nz with username habitation failed. Please can you check that your server settings above are correct? And if there is a bug? Irma

hi :-)

My Thunderbird uses between 19 and 34 GB of RAM. It's cyclical (with a period of about 10 minutes).

What do you suggest?

Do I need to perform a performance diagnostic? https://support.mozilla.org/en-US/kb/profiling-thunderbird-performance

Do I need to follow all the steps listed on https://wiki.mozilla.org/Thunderbird:Testing:Memory_Usage_Problems#Diagnosis_Steps, or can I skip some of them?

Hi, I use gmail and yahoo as my onlline emails. Gmail is primary and Yahoo is secondary. I'm frequently prompted to login to Yahoo. (via pop up) New to me. I reimaged my laptop recently. Did I forget something either w/in TB or Windows? I;ve relooked at all my szettinngs. Nothibng seems amiss. Thanks for your help!

I imported a US_Holiday. ics calendar file in to Thunderbird/Lightning. How do I remove the all of the events that calendar imported? It has junked up my regular calendar with not wanted holidays and observances.

Been to various sites for diag info. I have uninstalled antivirus and tried it, no joy. I have done all the following to each folder - compess, repair, deleted old emails, etc. (I actually have rules that are to do this automatically). I have captured config info, uninstalled and installed fresh. Still have the problem. -- and finally restored so I still have email addresses, etc. etc. This problem has started for me with in the past 2 weeks.

1) ALSO note: I am running W11 home. Mozilla keeps calling this W10. I do not know what the difference is between Home and Pro, but I am planning to upgrade to PRO within 2 months (looking for a reasonable deal on the cost of the upgrade). 2) Wife's computer is W11 Pro, she does not have the problem.

TB suddenly moves messages from inbox to trash automatically without any interaction. Search through the forrum shows that it has been asked for already, see https://support.mozilla.org/en-US/questions/1588804, similar postings can also be found with you search engine.

As described in other postings, the messages are moved from Inbox to trash. When moving them back manually from trash to inbox, they are moved to trash again immediately.

• it happens for the default account only,
• there're no filters at all in TB,
• junk detection is disabled,
• Settings->General Storage is all disabled,
• (account)->Settings->Server Settings has checked "move deleted messages to trash",
• (account)->Settings->Storage is all disabled,
• Inbox->Properties "Repair folder" does not help,
• Inbox->Properties "rules is set to "use account settings" (and greyd out "do not delete messages"),
• exactly same behaviour when starting TB in save mode,
• manually deleting all *.msf files (for inbox) does not help,
• manually deleting xulstore.json does not help,

Additional notes, which are not related to the problem, IMHO:

• IMAP on port 993,
• no other clients anywhere are connected to that account,
• TB configured for more than 10 accounts, more than 500 folders and sub-folders,
• host with > 16GB RAM, TB uses 3GB virt,
• problem observerd in older TB also, at least 13x.x

I'd be happy to debug/trace the problem if someone can give me detailled insructions how to start TB with debugging. Please feel free to ask for about:config settings as they are non-ambiguous and language independent ;-)

Thanks.

Hi!

I am using Ubuntu 26.04 with Gnome 50.1 (kernel 7.0.0-28-generic). I installed Thunderbird 1:140.13.0+build1-0ubuntu0.24.04.1~mt1 amd64 from source (140.12.1esr).

When I receive an email, I get a system notification where I have an option to "Mark as read" or "Delete". For most emails, if I click on "Mark as read", the email will be marked as read. However, Thunderbird has the feature to automatically put emails into Junk. And if I click on "Mark as read" for emails that are going to be automatically put into Junk, the emails will remain unread. It would be nice to mark the junk emails as read when I click on the button.

Thanks in advance!

I have set a custom theme on my Thunderbird on Linux. As you can see by the attached image though, the menu bar is hard to read when you get to the right side. Dark background and dark text doesn't really go together. Is there a way to make the background of the menu bars a solid color or something less see-through so the text can be read? I want a light theme, but I need to be able to read the menu.

happens on Windows 11 also

Every birthday or holiday reminder (I haven't entered these) generates an error when i select snooze or snooze all. The reminders I have entered snooze fine. Using gmail calendar.