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Hello I was using Thunderbird on a Windows 7 PC and I want to migrate to a Windows 10 PC. I can't retrieve my emails even though I'm following the transfer procedure between 2 Windows PCs. I copy the 2 directories %appdata local and roaming I should point out that I had changed the message storage location in the server settings to have it on the D: partition, which I back up regularly. When I start Thunderbird, it will obviously search for unread messages on the Orange server, but I cannot find all the history that I had on the source PC. Thank you for your help Daniel

J'utilisais Thunderbird sur un PC Windows7 et je veux migrer sur un pc Windows 10. Je ne parviens pas à récupérer mes mails bien que je suive la procédure de transfert entre 2 PC Windows Je copie les 2 répertoires %appdata local et roaming Je précise que j'avais changé l'emplacement de stockage des messages dans les paramètres du serveur pour l'avoir sur la partition D: que je sauvegarde régulièrement. Quand je lance Thunderbird, il va manifestement rechercher les messages non lus sur le serveur Orange, mais je ne retrouve pas tout l'historique que j'avais sur le PC source. Merci pour votre aide Daniel

The last few days most of my emails have been tagged as ***SPAM*** and automatically moved to my Junk folder. I have to be sure to check that folder. I've tried "training the app by moving valid email to the inbox but the problem persists.

I checked the installed Programs on My Windows 8.1 laptop, and saw that two x86 versions of Thunderbird are installed - 115.10 on 05/07/2024 and 115.118.0 on 30/06/2025

Should I remove version 115.10?

Could two installed versions be causing the following to happen?

I have set incoming server settings correctly for each email account - outlook.office365.com SSL/TLS, OAuth2 and the outgoing server settings are correct - smtp.office365.com Port 587, STARTTLS, OAuth2

Microsoft is repeatedly requiring me to enter passwords for email accounts.

This message often displays: Login to server SMTP.Office365.com with username x failed.

When I click 'Send' I often receive: Sending of the message failed. Unable to authenticate to outgoing server SMTP-mail.outlook.com

and

Authentication failure when connecting to server Outlook.Office365.com

Advice on anything else I should check / change will be greatly appreciated. Thank you!

I exported a group email list from Thunderbird, edited the list (primarily by adding new names) saved the result as a csv. When I imported the list, first off I was NOT able to import the list as a separate group within my personal address book which was really annoying. I found another thread at https://support.mozilla.org/en-US/questions/1498090 where someone was having the same problem. So it appears there is no easy way to create an new group in Thunderbird under my address book

More importantly, ALL the email addresses I imported were mangled for example k_boreen@hotmail.com became k+AF8-boreen+AEA-hotmail.com

Fortunately, it looks like I still have the old addresses in addition to the ones I imported but it's going to be a pain to get rid of the mangled addresses

I'm on version 128.12.0esr

Thunderbird pushed out an automatic update last night (July 13 2025) to version 140.0.1esr. Since then I cannot complete creating and typing a new message without Thunderbird freezing completely during entry of the text of a new message. I am running Windows-11 home, version 24h2. I have rebooted, etc. multiple times. I also ran thunderbird in troubleshooting mode and the problem still exists.

Please help - as of today Thunderbird is completely useless to me.

wellerhn@gmail.com

Failure to download email from Optus. I have spent a number oif hours to no avail talking and typing with the Optus staff regarding this problem. 1. I can send email from TB but cannot receive. 2. I can see the incoming emails in their Webmail site. 3. Optus confirm my settings are correct for both the mail server and SMTP server. When I go to Settings> Security > Passwords > remove server so I can re-submit my password, the only one showing is the SMTP server. Should the incoming mail server also be shown?

I am frustrated and ready to dump TB but have bee with it many years and don't want to start again with another programme as I am 83 and am partially blind. Please can anyone assist?

I am able to receive emails on Thunderbird but I am not able to send emails to anybody from Thunderbird. That happens on two computers I have. I am able to send emails from Outlook. Therefore, it is not my email provider's (BluePeak) problem. When I try to send an email from Thunderbird, I receive the following error message: “Sending the message failed. SSL received a record with an incorrect Message Authorization Code. The configuration related to must be corrected.”

Please help me resolve this issue. Thank you very much!

Been this way for quite a while now. Deleted messages do not show up in trash in 1 gmail account. Properties of the trash folder indicate that it contains 124 meg. In a different gmail account all is normal. Properties indicate the same in both gmail accounts. Asside from maybe deleteing/reinstalling the account, how can this be fixed?

Error de envío de mensaje Falló el envío del mensaje. El mensaje no se ha podido enviar porque ha caducado la conexión al servidor de salida (SMTP) smtp.dazzlepremiumrefunds.com. Vuelva a intentarlo.

Hello!

I just observed a new issue with S/MIME. When trying to send an encrypted mail to somebody new, I get an error “End-to-end encryption requires resolving certificate issues with somebody@example.com”.

The message is not very helpful, and doesn’t propose any solution. So a web search gave me this article: Prerequisite for sending an encrypted email message. It states:

> If Thunderbird considers the email's signature and the sender's certificate valid, it will automatically be imported and available when you attempt to encrypt an email to that correspondent using the S/MIME technology.

When I open the sender’s mail, the signature is confirmed as valid by Thunderbird.

Ignoring the warning message and trying to send the encrypted mail results in the following error in the log: `mailnews.send: NS_ERROR_ILLEGAL_VALUE: Component returned failure code: 0x80070057 (NS_ERROR_ILLEGAL_VALUE) [nsIMsgComposeSecure.beginCryptoEncapsulation]`

So, I verified in my list of certificates for people, and that new person didn’t figure in the list. Other people did, the last one from 6 June.

Is it possible there’s a bug causing TB to not import the certificate when I open the mail? What would a workaround be? Is there a way to import a sender’s certificate manually from their signed mail?

After converting from Outlook to Thunderbird, I can see there are 23 unread mails in my Inbox. My problem should have a very simple solution, but I cannot find any. How do I filter my messages in the Inbox to show only those unread???

Bjorn B. Juvkam

I'm trying to send encrypted email to a recipient who I have a certificate for, but Thunderbird states:

End-to-end encryption requires resolving certificate issues for ....

That's rather unhelpful - what issues exactly? I've imported the CA certs into the system and they are shown in TB. openssl verify on the cert returns OK. I'm at a loss as to what might be the issue.