Thunderbird Community Forum

A few times I have missed messages that have have been inadvertently placed in the Accounts Spam Folder. Is it possible to to indicate that the Spam Folder has contents in the same way contents are indicated in other Account Folders?

I've been a longtime Thunderbird user on my desktop (laptop actually). I'm wanting to start using Thunderbird on my Android phone.

What I understand so far is that both the desktop and mobile have to have the same settings if I want to be able to send/receive (and have records) on both setups. I also understand that I need use IMAP settings.

In my situation, I believe I set up my desktop to be POP but to leave messages on server until I deleted.

So, my questions are these: Do I need to delete my POP accounts on my desktop first before adding the IMAP version of the account? If not, I can simply add the new account along side and then delete the old account. If I do need to delete the account, does deleting the account delete the emails as well? And how do I transfer any emails or sent emails from the POP to the IMAP?

In as much as I have several accounts to transfer, I want to make sure my step-by-step works well for one then I can proceed to all the rest.

Thx BobbyG:)

I am using thunderbird client on arch linux. I am trying to filter by adding "Reply-To" as a filter. If i look into the source of the email i am trying to filter (i get like 100s of spam messages and only the Reply To seems to be from the same domain in the end) the Reply-To appears in there.

Any idea how to fix that? The other rules work fine, this one only seems to not work

I have had Thunderbird from the time I acquired my Mac computer. This week it started to do something new. After a restart I opened Thunderbird. A box came up that says across the top System Integration. The cursor balloons, and hasn't stopped for the time I powered the computer, as least fifteen minutes. You know how the program icons are in a dock across the bottom. With other browsers open, hitting the Thunderbird icon doesn't bring its window into the forefront. This needs either a reset, or possibly a backup first. Is there a quicker way to fix this? Thanks in advance. I am not using a VPN; but I also have Thunderbird on my Windows 11. You might have seen a more recent thread on that installation. I included a screenshot. It was easier here to do that than on the Windows 11. On the Mac, I just had to use Activity Monitor to close out of Thunderbird in order to get its version.

I am assisting an elderly user with a personal @hotmail.com account that receives email successfully in Thunderbird but cannot send. I have confirmed they can send and receive emails from their online outlook.com portal. The user's computer setup is as follows:

• Windows 11 (with latest updates).
• Thunderbird 153.0.2 (64-bit).
• A personal @hotmail.com account with the following server configurations:

  -> Incoming IMAP: outlook.office365.com, port 993, SSL/TLS, OAuth2, and
  -> Outgoing SMTP: smtp-mail.outlook.com, port 587, STARTTLS, OAuth2.

Thunderbird successfully authenticates to Microsoft using OAuth2 for incoming email. However, when Thunderbird attempts outgoing email authentication, Microsoft's SMTP server rejects the authentication. The Error Console in Thunderbird records this message: "535 5.7.139 Authentication unsuccessful, SmtpClientAuthentication is disabled for the Mailbox."

-> Refer to attached image: "Thunderbird Error Console_20260811.jpg". -> I am able to provide a short screen recording demonstrating the failure if needed.

To try and resolve the above, I completed the following actions:

1. Confirmed Thunderbird is current (153.0.2).
2. Confirmed SMTP is configured for OAuth2 rather than Normal Password.
3. Confirmed port 587 and STARTTLS.
4. Re-authorised the Microsoft account/OAuth connection.
5. Confirmed IMAP OAuth2 works.
6. Confirmed Outlook.com webmail can send successfully.
7. Reviewed Mozilla's current “Microsoft OAuth Authentication and Thunderbird in 2026” guidance, including the section covering cases where IMAP/POP works but SMTP does not.
8. Captured the SMTP failure in Thunderbird's Error Console.

However nothing worked, so I raised the matter with Microsoft support and eventually had the matter referred to their Tier 2 team. The Microsoft case number is: 7107041963.

Microsoft Support confirmed that for a personal Outlook.com/Hotmail account there is no user-accessible mailbox-level SMTP AUTH setting, and advised that SMTP is enabled by default for supported clients. However, because sending from Outlook.com webmail works, Microsoft Tier 2 declined to investigate the SMTP server response further and directed me to Thunderbird support.

I am able to provide a copy of the chat transcript if needed.

In any event, the TLDR version IMAP works using OAuth2, but SMTP using OAuth2 fails because Microsoft's SMTP server reports SmtpClientAuthentication is disabled for the Mailbox. Microsoft Tier 2 has referred the issue to Thunderbird support.

Questions:

1. Is this a known current issue affecting personal Outlook.com/Hotmail accounts using Thunderbird?
2. Is 535 5.7.139 SmtpClientAuthentication is disabled for the Mailbox known to occur with Thunderbird OAuth2 even though IMAP OAuth2 succeeds?
3. Is there a current Thunderbird-side workaround or alternative SMTP server/configuration recommended for personal Hotmail accounts?
4. Would changing the SMTP server from smtp-mail.outlook.com to smtp.office365.com be appropriate for a personal Hotmail account in Thunderbird 153, or should the current Microsoft-documented server be retained?

-> I note there appears to be conflicting advice on this point in previous support threads.

1. Given that IMAP OAuth2 authentication succeeds for the same Microsoft account, does this indicate that Thunderbird's Microsoft OAuth authorisation itself is functioning correctly, or could SMTP require a separate permission/token that may be failing?
2. Are there any additional Thunderbird logs or diagnostics I can provide that would help resolve this matter?

Disclosure: I used ChatGPT to help organise my troubleshooting notes and technical details for this post. The troubleshooting, observations and diagnostic information described above are from my own work on the affected PC.

Sometimes an email I receive contains text whose right margin and text is chopped off. I thought this was because the emails were formatted for Google's gmail, but I just received an email from Thunderbird itself that is truncated this way. What's going on?

I'm enclosing a screen shot. I can also send the .eml file if that's helpful.

TB guidance is to maintain separate profiles for dual-booting (Kubuntu and Win11), rather than sharing the profile. That adds to IMAP churn, but also to disk space, of course. But the biggest concern is keeping Local Folders (a very large archive which is by far the largest part of my profile) coordinated: both sides must access the same Local Folders.

The option to specify "Message Storage" for Local Folders obviously addresses that problem: both Kubuntu and Win11 can have the same NTFS Local Folders storage. At the same time, each IMAP account also has the option to specify its own "Message Storage" "Local Directory" location outside of the profile folder. That suggests two obvious questions:

1. Why not specify shared storage for each account, as well as for Local Folders?
2. After Local Folders and all accounts are shared, then precisely what, from each profile, cannot be shared between Kubuntu and Windows? Does this bring us back to asking why the profile cannot simply be shared?

[Years ago, when my email accounts were POP, I had no problem sharing a profile between WinXP and an earlier Ubuntu variant. (Of course with POP, they had to share.) Is today's separate-profiles guidance related to IMAP accounts or to some other change in TB design?]

1) How do I get the emails Thunderbird marks as spam to be moved to the Spam folder without me doing anything. I have thousands of emails now most marked as spam but I have to go in and move them one by freaking one!

2) Also you freaking filter system doesn't work worth a crap! I have created filters for instance: for any emails that have @cypress.com in the From part of the message to be moved to a folder under my inbox named Cypress. I have run it many times and actually none of the filters I've created work? They are very simple to understand and I am doing them correctly as far as I can tell but they don't work. I have created at least a dozen filters and the only emails moved are ones I moved manually myself.

And this training crap you have I don't know what you think it should take a computer to learn to move something to a folder. It's not like a child that has to be taught how to spell. You tell it if it has this in whichever field you've selected then it should move it. Not have to be taught? Not a bright idea in my opinion. It's why AI isn't very smart at least what they release to general users. Anyway I digress.

If you can help me with the above issues in the above paragraphs 1 & 3 I would greatly appreciate it.

I have 10 email accounts I have to monitor. When I set up Thunderbird on Windows, I entered all the account info and the passwords. I checked the box 'use password manager'. This worked well for a few days. After several days, I started the app again and it asked for every password again. I entered all the passwords again. This happened several more times. I sought help for the bug, but found none. Someone suggested deleting password database files in the Thunderbird data folders. This did not help. Someone else suggested that CCleaner may be deleting password data files, so I added the entire Thunderbird data folder to the scanner exclusion list. Yes, this may be a security risk, but I need this app to work, as I have not found any other app that even begins to get the job done. Ready to start looking for another email app now, unless someone can fix this problem. It is not reasonable to expect me to lookup and restore 10 passwords every time I check my mail.

Recently I moved from a Thinkpad X1Yoga running Mint and Windows 10 to a Thinkpad P14s running Kubuntu and Windows 11 Pro 25H2. On the Win11 side (which behaves differently from Win10), there are installation issues affecting both Firefox and Thunderbird.

Win 11 Settings lists: under Apps > Installed apps

• . . . (other apps)
• Mozilla Firefox (x64 en-US) 154.0
• Mozilla Maintenance Service 153.0
• Mozilla Thunderbird (x64 en-US) 153.0.2
• . . . (other apps)

under Apps > Default apps

• . . . (other apps)
• Firefox
• Firefox
• . . . (other apps)

That is, Default apps lists Firefox twice (though not as "Mozilla Firefox"), but Thunderbird not at all. This causes two problems:

1. It's not clear which Firefox to choose for browser protocols.
2. There is no Thunderbird to choose for mail-related protocols,

Can someone tell me why the Installed apps and Default apps list differ, and how to set the appropriate defaults for Firefox and Thunderbird?

Thanks, John

Comcast/Xfinity forced me to change my email password. I entered the new password when prompted by Thunderbird. I am receiving email from my comcast email account. But anything I send from that email account shows this error: "Sending of the message failed. An error occurred while sending mail: Outgoing server (SMTP) error. The server responded: resomta-c2p-555442.sys.comcast.net resomta-c2p-555442.sys.comcast.net ESMTP server not available (9009/146.70.230.100)."

I've tried changing the SMPT port to 587 because an online search suggested that might work. The error message changed slightly but it will still not send.

Here are my current "Details of selected server": Description: Comcast Server Type: SMTP Outgoing Server Server Name: smtp.comcast.net Port: 465 Authentication method: Normal password Connection Security: SSL/TLS

When I click on "test connection" I get a green check mark and the note "Successfully established a secure connection to smtp.comcast.net:465.

What now?

I spend the last hour or so in sheer panic and doubting my sanitiy as an email I was just reading disappeared from every mailbox I have here (I have 8 mailboxes in Thunderbird) . Also for whatever reason search is missing from the title bar.

The email was "archived" by Thunderbird inthe "Local Folders" I never use local folders as local folders is silly in 2026 imo. I have my own mailserver which is perfectly save and backuped and stuf I don't need yet another location were mail can hide.

Anyway that was a bit of a rant. This would not have happend if this sille ¨Local Folders" didn´t exist at all. But I seem unable to get rid of it.

How do I remove ¨Local Folders" from Thunderbird?

Can't drag and drop attachments from Thunderbird into file manager. I get a windows message box that says "Unspecified error" white cross on red circle. If I drag and drop with the control key held down it creates a file of zero length in the selected destination, It's not running as admin. Problem only just occurred.

Does anyone no why I would keep getting these types of messages. Also the only glitch I've experienced is occasionally in writing an email it fails to save to draft. Thanks.