Thunderbird Community Forum

I am trying to replace my Outlook account which has been blocked by Microsoft AI and remains blocked after multiple attempts to get it working again. I have just added a new account and can send @mail.uk e-mail from Thunderbird. However, there is only an in-box folder shown on Thunderbird and no trace of the sent e-mail - although I can confirm that is was received by two test recipients. I did consider a Thunderbird e-mail account as a replacement but, at 79, I avoid additional costs whenever possible. Can you suggest an alternative free e-mail service which works on Thunderbird? My g-mail account used to work but now I am having password problems.

I swap computers about 3 times in year, and not all of mine emails seen to have transfer. I was wondering if there is any way I could potentially recuperate those emails.

Hello everyone. From time to time, the "Attachments" button stops working. It can be clicked, but nothing happens. Occasionally, restarting the PC or the email client helps. More often, the only solution is to reinstall the entire program—which also means losing access to years' worth of emails, as I then have to wait for them to be re-downloaded from the IMAP server. What should I do? I’m using the latest versions.

I was referred here from Thunderbird Bugzilla report 2081665.

We are experiencing a recurring problem with Thunderbird 153 on several Windows workstations in a business environment.

The important point is that the problem also occurs with completely new Thunderbird profiles created from scratch. It is not limited to migrated or old profiles.

On one workstation this has already happened to three separate Thunderbird profiles.

Typical sequence:

1. Thunderbird 153 is installed. 2. A completely new profile is created. 3. Mail accounts are configured manually. 4. Everything initially works normally. 5. After some time the profile begins to malfunction. 6. Thunderbird Settings no longer open/respond. 7. The address books still exist, but address autocomplete when composing a new message stops working. 8. Creating another new profile temporarily fixes the problem, but the same behavior can return later.

Troubleshooting already performed:

- Troubleshoot Mode - extensions disabled - tested without the existing prefs.js - rebuilt Thunderbird caches and profile UI state - recreated indexes/databases - completely removed Thunderbird from Program Files, AppData\Roaming and AppData\Local - clean Thunderbird installation - clean profile created from scratch - Thunderbird executable and profile paths added to Kaspersky Endpoint Security trusted applications/exclusions

Removing prefs.js from an already affected profile did not restore the Settings window.

A clean test profile initially works correctly.

We have also encountered this behavior on other workstations. Some users have more than 100 message filters and many folders, so rebuilding profiles repeatedly causes significant administrative work.

Several affected computers had Windows user accounts renamed in the past.

We also experienced a separate issue where the Attach File dialog stopped appearing while drag-and-drop still worked. Bugzilla identified this as the already known Bug 2077590, so I consider that a separate issue.

For comparison, after completely cleaning Thunderbird from an affected workstation and installing Thunderbird 115.3.1 with a clean profile, the same workstation currently works normally.

Because freshly created Thunderbird 153 profiles can later develop the same problem again, simply recreating the profile does not appear to be a permanent solution.

Environment:

- Windows workstations - Thunderbird 153 ESR - Kaspersky Endpoint Security - multiple IMAP accounts - business environment

What diagnostic information should I collect from the next affected profile before replacing it?

I can provide:

- Thunderbird Troubleshooting Information - Error Console output - profile file names/sizes/timestamps - Windows Event Viewer logs - sanitized prefs.js - comparison with a working fresh profile

Bugzilla report: 2081665 Known separate attachment bug: 2077590

misconversion (mojibake) does not happen when a mail header is as below. Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: base64

misconversion (mojibake) happens when a mail header is as below. Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit

It seems encoding in my Thunderbird does not match 8bit. Several years ago Thunderbird had an option to modify text encoding but I cannot find such an option in the recent versions. It would be really appreciated if anyone help. Thank you.

Haven't been able to get into Thunderbird since 9/26/26, every time I try it keeps asking me for my password. I key it in and it does the same thing. I have had someone to come up and look at it, but they weren't familiar with thunderbird, I have been having to use Kinetic email, don't like it. hate gmail.

Dear Support

Kindly help me in solving the problem of not being able to attach files in my Thunderbird emails. Thank you Yours sincerely Ana Cristina Figueiredo

I received an email from Thunderbird (my email provider) wanting me to join the Early Bird Beta but their link to pay with PayPal didn't work so they requested I add a new credit card. I use PayPal often so I know my card on file with PayPal is OK. Seemed odd to me for their request. I could forward their email to me if needed. Looks like they are using Paddle.com Market Limited.

Hi I am at my wits end here - The date in my Thunderbird is behind by 1 hour. This is affecting sent messages and also received messages.

This just started today. For over a year, the time has been correct. I have not changed any settings in Thunderbird prior to this issue.

My Win11 computer shows the date and time correctly.

I had a Win11 update yesterday. Not sure if that has affected Thunderbird (My province - Manitoba Canada - also stopped using daylight time changes in the last couple of months.) We are now permanently CDT, and is UTC/GMT -5 - which is what it shows in my Win11 setting.

My timezone and time in Win11 settings shows correctly.

Just to see if it would make a difference - In Win11 settings->Time & Language - I changed the time zone automatic to off (even tho the time zone showed correctly) and set it manually to UTC-5:00 Manitoba, - I changed 'Set Time automatically' to off, set the time manually and synced the time.

No difference with Thunderbird.

Why is my time off in Thunderbird?, and what can I do or check to fix this?

Was unable to edit appointments attempts placed a previously unknown dialog box. Search for info found one person advised Select Calendar (tab), edit, calendar properties and uncheck the read only box.

In my case the box was already unchecked, checked it, tried it, same result. Unchecked it, tried it same result (not able to edit).

Next I thought maybe some data location is not being changed. So I closed all files, shut down (not a restart) my machine, and restarted it. Opened Thunderbird and tried to change an appointment, did not work. Went to Calendar (tab), edit, calendar properties and found the read only box checked. Unchecked and all seems back to normal operations now.

Since the Thunderbird update of 30 Sept the ability to attached files to my emails has 'vanished'. I press the attach 'button' but there is no response. Never had this as a problem before. I am running Windows 11 home version. Help!

I keep getting the following (see attached image) when I try to open my Thunderbird. I tried to unsuccessfully open safe mode because it still asks for a password from my very old BlueHost account. I previously worked with AI on this and deleted all BlueHost lines I could find in my account. View the image I have included and see all the messages that include BlueHost. They must be hiding somewhere in Thunderbird. I am not sure what version I have because I cannot open it. Please help! I be happy to send you my phone number is needed.

Hello,

I'm moving to Graph from EWS and have followed the instructions at: https://support.mozilla.org/en-US/kb/microsoft-ews-graph-migration

I get through to screen that offers Graph API as an option, alongside IMAP, POP3 etc, and click on Graph API which directs me to my browser to log in to my email service (via GoDaddy). I log in successfully which takes me to the Thunderbird 'You're All Set' screen saying the account has been securely connected to Thunderbird and therefore ok to close that screen.

Back on Thunderbird it then progresses but returns with "Authentication Error - unable to log in at server. Probably wrong configuration, username or password".

The username and password are correct, and there aren't any other options available when editing/manually configuring the connection...so at a dead end, alas.

Any pointers much appreciated!

When editing a contact in Address Book, after selecting a time zone from the drop down menu and saving the contact, only the first 7 characters of the time zone string are displayed in the contact view. When reopening the contact for editing, the time zone field is shown as empty again.

Using Thunderbird 115.18.0esr Supernova 64-bit on Mac laptop OS 10.13.6. Worked fine for years, with ongoing Thunderbird updates, even though Mac OS is 32-bit. Suddenly, after 10/6/26 can't retrieve emails although I can see them on the ATT Yahoo server website. Can still send emails with Thunderbird. Inbound server settings are: POP server inbound.att.net, Port 995, SSL/TLS, Normal Password (I long ago created a Secure Mail Key, and even tried creating a new one). But inbound server name doesn't show in Saved Passwords (only outbound server with Secure Mail Key as password)? I have tried everything suggested, repaired my inbox folder, updated Thunderbird files, etc. in Profile as recommended. But still no prompt for password when attempting to get messages. Just shows "Done" at bottom left with no new messages received. But new messages are seen on server website. So it appears that Thunderbird isn't able to connect to the ATT Yahoo server to get emails. Why? And what else can I do? I love Thunderbird and want to continue using it.

I have been getting the following error message each time I log into my email today: " The STAT command did not succeed. Error getting message number and sizes. Mail server pop.bluedomino.com responded: [SYS/TEMP] Internal error occurred. Refer to server log for more information. [2026-10-14 12:31:46]" I get a message for each of my email accounts. My spouse also gets the message on hers. The server we use has just been transfered from Blue Domino to Network Solutions.

A week ago my sent emails were being rejected and the error message included something about bluehost (I called them and it was fixed within the day). Now it's happening again and my error message says:

host eig-east.smtp.a.cloudfilter.net [3.228.35.199]

   SMTP error from remote mail server after end of data:
   550 Connection Rejected - see http://www.spamhaus.org/query/ip/162.241.218.139 AUP#BL

I receive emails yo simon@padworks.plus.com, but cannot send them, with a message saying ...

Sending of the message failed. An error occurred while sending mail. The mail server responded: Unknown sender. Please verify that your email address is correct in your account settings and try again.

please also reply to simondowthwaite246@gmail.com