Thunderbird Community Forum

In TB prior to v.155, folder message counts were not shown at all if the respective folders were empty. That is, instead of showing "0", TB did not show anything.

Now, after updating to TB v.155.0.1, I see dashes (horizontal lines) in the folder tree to the right of each empty folder.

Is it possible to revert back to the original behaviour and get rid of those unsightly dashes? They only add visual clutter (my opinion, obviously) while not providing any extra information.

Thanks.

My Thunderbird version is 153.2. My email provider is Yahoo.. I use the POP protocol and have set it up so that messages are left on the server for this particular email address because I want to hang on to several important emails. I am not sure if I should be checking "Until I delete them" but it is checked right now. Leave messages on server for X number of days is unchecked. I also have a few other Yahoo mail addresses on Thunderbird also set up using POP but the messages are set up to be deleted on the server so they seem ok so far.

Basically when I delete messages in Thunderbird, it also deletes my messages in my Yahoo webmail inbox and it goes to the trash. When I delete messages directly in my Yahoo webmail, nothing happens. So I then transfer the emails that ended up in trash of my Yahoo webmail to my inbox and they are of course downloaded again to Thunderbird. When I delete these emails in Thunderbird thinking that nothing will happen in my webmail since it is set up to POP and messages left on the server, the messages get deleted again, causing an endless cycle of transferring emails to inbox, downloading them on Thunderbird, deleting the unwanted emails on TB, then seeing all my other emails disappear on my Yahoo webmail inbox.

It started a few days ago. There was a random glitch (not sure if it was on Yahoo's end) that led to the OAuth dialog window popping up every time TB downloads mail from Yahoo. Initially I didn't handle this properly and it led my inbox emails going into my other Yahoo mail accounts. I have finally fixed that glitch and emails appear to be downloading properly to their respective inboxes. But I cannot seem to figure out what is causing my emails to be deleted from the POP server. Should I be unchecking "Until I delete them"?

I have been trying to set up Thunderbird Mobile on my Android phone. I scanned the QR code to export my settings. However, when I open the app on my phone, the only options I have are "Add an email account", or "Sign in with Thundermail". The instructions state that clicking on "Get Started" should bring up the option to "Import Settings" but it does not.

I have recently closed my yahoo mail account, removed all traces from Thunderbird, but when I start Thunderbird, after a few seconds, I get a Yahoo sign in screen over the top of Thunderbird

I receive this reply when launching email: "Looks like there’s a problem with this site https://outlook.office.com/owa/ sent back an error. Error code: 401 Unauthorized Check to make sure you’ve typed the website address correctly."

Since yesterday (15 September 2026), my Microsoft Account has not been working properly. I managed to get round the problem by deleting my cookies. Then the update to version 156 was released, and after that Eule became incompatible. When can we expect an update to make it work again? Thanks.

I have been using Thunderbird for a while.. I could always filter messages easily to help with mailbox cleanup, now it seems to have stopped working or a setting has automatically changed.. When activating Quick Filter, I could type in the 'Filter Messages' box and it would start listing the mails in that inbox as I typed, now it doesn't happen anymore..

Thunderbird suddenly stopped working properly today, 15 September 2026. Webmail for the same email account is working normally: I can both send and receive messages. However, Thunderbird is having problems with both incoming and outgoing mail. • Thunderbird connects to the IMAP server, sometimes very slowly, but then does not retrieve new messages. • Sending a message from Thunderbird fails because it cannot connect to the outgoing SMTP server. • Thunderbird's own update also fails. This has never happened to me before. • I have restarted Thunderbird and also restarted the Mac, but the problem remains. • I have not changed any Thunderbird account settings. The fact that webmail is working normally makes me wonder whether this is a Thunderbird problem rather than a problem with the email service. Has there been a known Thunderbird problem affecting connections to mail servers or the Thunderbird updater, and could these problems be related

I can not create a new email account for the email : info@ecomtehpro.ro. I have already an email account: office@ecomtehpro.ro. Please give me a solution to create the new email account. Thank you.

I've been using Thunderbird version 155.0 with only a few issues (reported in other posts).

To investigate one of the issues I've had to create a new profile for testing. I've managed to set everything up except for my default font for outgoing emails. If I send an email with say, four lines of text, I can format each line to be a different font and the received email reflects the different fonts for each line.

But Thunderbird isn't remembering the last selected font. So if I send a second email (without re-selecting any font) the recipient receives it in some naff mono-spaced font. I guess there's somewhere where I can set up the default font for my outgoing emails but I haven't managed to find it yet. Can anyone help?

Hello fellow Thunderbirds,

I have been using Thunderbird for years and had thousands of emails in quite a few folders, with a shit-tonne of filters etc. My emails were running pretty well. I only use two addresses, but the folders help manage everything.

I just got a new computer last week. Prior to switching over to the new computer I read through the 'Export your Thunderbird Profile' help page, and the 'Move Thunderbird data to a new computer' pages. I've tried to follow all the info there (with a glitch, explained below).

I am using a Windows system and have gone from Win10 to Win11.

I have the following data:

• Mozilla Maintenance Service (in Program Files (x86) ).
• Mozilla Thunderbird (in Program Files (x86) )
• Thunderbird (In Users/Username/AppData/Local/Thunderbird) (Contains 'profile' and 'updates'

I tried to swap the above data into the same spots on the new computer, but alas, it's not working. I *may*, however, have fucked it up myself...

So... When I got the new computer, I immediately downloaded Firefox, but, alas, I entered my email's details before closing it down. It did download a few off the server, but only a day's worth (before I realised I screwed up).

As soon as I realised I'd mucked up, I uninstalled Thunderbird and deleted the files on the new computer (you know how when you download it doesn't always remove all the stuff, so I tried to do this).

I reinstalled Thunderbird, but closed it prior to loading the email addresses on (as instructed). I then transferred all the above data into the corresponding file areas on the new computer. However, everytime I try to run the program it just goes to the standard open screen (with the popup that prompts you to enter your email addresses and details into it - see image, below, in case I'm not explaining it right).

Anyway, I'd appreciate any help you might be able to give me as I'm desperate to get my emails running again and have access to all the saved emails which were in my system. Kindly. Larysa.

Thunderbird comes up as not responding - tab names appear but he last tab is constantly trying to open. This began about 2.00pm Tuesday 15th September. Shutting down & restarting has no effect - please help!! Brian

Greenby Support wants a screenshot of Thunderbird Outgoing Server (SMTP) which I can't find via the App menu or any other means of searching. So I do not know which version we have re your question below and I have chosen one shown at random to allow me to submit my question

I am trying to send an S/MIME encrypted email from Thunderbird to:

jobcenter-chemnitz.netzwerkpartner@jobcenter-ge.de

The recipient certificate is provided by the official certificate directory of the German Federal Employment Agency (Bundesagentur für Arbeit).

I downloaded the recipient certificate and successfully imported it into Thunderbird under:

Settings → Privacy & Security → Certificates → Manage Certificates → People

The certificate is displayed correctly there. The email address contained in the certificate is:

jobcenter-chemnitz.netzwerkpartner@jobcenter-ge.de

The certificate is valid from July 29, 2026 to July 29, 2028 and includes E-mail Protection and Key Encipherment.

The required CA certificates are also installed:

BA-Class-1-Root-CA-4:PN BA-VPS-CA-11:PN

However, when I compose an encrypted email to this exact address, Thunderbird reports:

“You have selected to encrypt this message, but the application failed to find an encryption certificate for jobcenter-chemnitz.netzwerkpartner@jobcenter-ge.de.”

Under S/MIME → Recipient Certificates, Thunderbird also shows the certificate as “Not found”.

I have already tried:

deleting and re-importing the recipient certificate completely restarting Thunderbird after importing it manually typing the recipient address in lowercase without using autocomplete checking the complete CA certificate chain temporarily disabling OCSP

None of these changed the result.

My own personal S/MIME certificate works correctly. As a test, I can compose an encrypted email to my own email address without any certificate error. Therefore, the basic S/MIME configuration and my own certificate appear to be working.

When I reproduce the problem with the Thunderbird Error Console open, I get:

NS_ERROR_ILLEGAL_VALUE (0x80070057)

related to:

nsIMsgComposeSecure.beginCryptoEncapsulation

This seems similar to Mozilla Bug 2021265, where a manually imported recipient certificate is visible in Certificate Manager but is not found when composing an encrypted message.

Is this a known issue in Thunderbird 140 ESR, and is there a workaround for using this manually imported recipient certificate?

I’m trying to understand how Thunderbird handles links to online media when an email contains a link to a photo or video rather than a normal attachment.

For example, if an email contains a link to public Instagram media, I may open it in the browser and use a browser-based option such as Indown.mobi to work with the media. Is there any Thunderbird setting that affects how these external media links are opened or handled?

I’m mainly interested in understanding whether Thunderbird treats these differently from normal attachments and whether there is a recommended workflow for managing them.

Hi All,

I am on the latest release 156.0 on Windows 10. I have 3 email accounts, 2 gmail and 1 yahoo. The Yahoo account has been giving me problems since the last 2 weeks. Mind that yesterday I have a completely new Windows 10 installation so also TB installation is new.

I have renewed the Oath login, all messages were downloaded without a problem, but once in a while I get different notifications about server errors such as the ones below. There's also a third type of message error but haven't been able to get a screenshot of it.

Could someone please help me to solve this issue? I really don't understand why the problem is intermittent. Thanks in advance!

Hi, Every time I start Thunderbird from a cold startup, I get the message: Authentication failure while connecting to server outlook.office365.com then.... everything works fine from then on. I can send and receive normally. This can also sometimes happen when I close thunderbird and restart during the day - but not always ! Obviously all the outlook sign-in settings are OK, as it works fine for the rest of the day. Is this known/common/fixable ?

Regards, Paul

Windows 11 (26H2) Thunderbird 156.0 (64-bit)

Anyone know how to use the new setting "mail.addr_book.add_item_default_uri" in 155? The default value is a URI, "jsaddrbook://abook.sqlite", how do I figure out the URI of an alternative? I want to point it to my CardDAV server, do I just set it to the CardDAV URL?