Prevent Thunderbird from stripping custom headers (e.g. X-Alias) on sending

Hi everyone, I'm working on a privacy-friendly email setup and ran into a challenge with Thunderbird. My setup: I have a catch-all email address that forwards all incom… (read more)

Hi everyone,

I'm working on a privacy-friendly email setup and ran into a challenge with Thunderbird.

My setup: I have a catch-all email address that forwards all incoming emails sent to *@mydomain.com to my real mailbox, secret@mydomain.com. This way, I can use aliases like alias1@mydomain.com, alias2@mydomain.com, etc., without exposing my actual address.

This part works perfectly.

The problem: When replying to a message sent to alias1@mydomain.com, Thunderbird automatically uses secret@mydomain.com as the sender address. That defeats the purpose — the recipient now sees my secret address, which I wanted to keep hidden.

Thunderbird offers a workaround via identities, but it requires creating a separate identity for every single alias, which becomes unmanageable if you use a lot of them.

My attempted solution: My idea was to have my mail server insert a header like:

X-Alias: alias1@mydomain.com

Then, on sending, the server could rewrite the From: header using that value — thus preserving the alias and protecting my actual address.

However, I discovered that Thunderbird strips custom headers like X-Alias when sending. That breaks the solution.

My questions: 1. Is there any way to configure Thunderbird to preserve specific custom headers like X-Alias during sending? 2. Alternatively, is there a better or recommended approach to achieving what I’m trying to do — replying from the alias address automatically, without exposing the real one, and without creating hundreds of identities?

I’d really appreciate any ideas, insights, or suggestions. Thank you!

Asked by fisoc70290 19 hours ago

After update July 25, the Outlook accounts fail to open. Says something about cookies not enabled on browser.

Windows 11 64bit. I have Outlook and Gmail accounts. About 6 months ago the Outlook accounts stopped sending messages. Ok, I can live with that as I only use them sparing… (read more)

Windows 11 64bit. I have Outlook and Gmail accounts. About 6 months ago the Outlook accounts stopped sending messages. Ok, I can live with that as I only use them sparingly. I tried lots of tweaks from this forum but none worked. I am not technically minded so I may have interpereted the wrongly. After the last update 9/10 July 25, the Outlook accounts fail to open. Says something about cookies not enabled on browser. I added the logins to the exceptions but no change. The cookies show on the list as on the PC. So I can't use Outlook anymore. Gmail. Now I can't send any messages from Gmail accounts. Just waits ages and says try again. The email I was replying to disappeared from my inbox when I logged through Google Gmail account. It shows on Thunderbird. I also tried to set up a new Gmail account on Thunderbird, would let me. So now, Thunderbird is useless to me. Shame, I liked it and even donated. How could something go from good to useless in one update?

Asked by generic111170 3 days ago

Last reply by generic111170 1 day ago

Why Emails not together?

Hi, at the top of the picture are 6 emails. Towards the bottom, highlighted in blue, is another email, RPAiken4@gmail. How can I get that one to be in the group of 6? … (read more)

Hi, at the top of the picture are 6 emails. Towards the bottom, highlighted in blue, is another email, RPAiken4@gmail. How can I get that one to be in the group of 6? TYIA

Asked by richardCPreston 3 days ago

Last reply by richardCPreston 23 hours ago

How to export all 3 Outlook classic email accounts that are cox.net addresses info now on Yahoo to Thunderbird on my pc, not in the cloud?

My ISP is cox.net. Cox migrated all accounts to yahoo.com, but still get downloaded into classic Outlook as pop3 with my cox.net addresses. I hate IMAP; I am 1 user with … (read more)

My ISP is cox.net. Cox migrated all accounts to yahoo.com, but still get downloaded into classic Outlook as pop3 with my cox.net addresses. I hate IMAP; I am 1 user with one PC and don't want anything synced in the cloud. Yahoo doesn't have my contact lists. When MS stops supporting pop3 in October, what do I do? My email address is my user login for most of my accounts. I'm desperate. Please help. Thank you.

Asked by BTINAZ 23 hours ago

140 change gray interface with addon?

Ciao :) I used to use these add-ons Old Icon Phoenity Buttons Phoenity Icons to make Thunderbird more attractive, but now I'm having constant problems. The inter… (read more)

Ciao :)

I used to use these add-ons

Old Icon Phoenity Buttons Phoenity Icons

to make Thunderbird more attractive, but now I'm having constant problems. The interface has become schizophrenic, and every time I open it, the icons have a different style, so I've been forced to disable the add-ons.

The question is, are there any supported add-ons left? I can't find any on the website. :(

Asked by Furio Sassi 5 days ago

Last reply by Furio Sassi 1 day ago

meassge on sign-in

recent pop-up when signing in to my mail acct. "sign in with google...sign in to continue to Mozilla thunderbird email" allows me to continue if i ignore it, but keeps co… (read more)

recent pop-up when signing in to my mail acct. "sign in with google...sign in to continue to Mozilla thunderbird email" allows me to continue if i ignore it, but keeps coming back. also pops up if i attempt to add a task to calendar. suggestions? thank you

Asked by js_consulting 4 days ago

Last reply by js_consulting 1 day ago

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Asked by kggr1993 1 day ago

Last reply by kggr1993 1 day ago

Thunderbird not add href tag to links even when specified

After the latest update, when I insert link and fill out both fields the href is not being populated in the anchor tag rendering the link inoperable. I had to hand code t… (read more)

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Asked by jake9 1 day ago

Thunderbird can't send mails with personal outlook account

I can't send any emails with my personal outlook account. It always says "Login to server smtp.office365.com with username xxx@outlook.com failed." Receiving mails works… (read more)

I can't send any emails with my personal outlook account. It always says "Login to server smtp.office365.com with username xxx@outlook.com failed." Receiving mails works fine. Both my IMAP and SMTP authentication are set to OAuth2.

Here's my account info found in troubleshooting information.

   account14:
     INCOMING: account14, , (imap) outlook.office365.com:993, 3, 10
     OUTGOING: , SMTP.office365.com:587, 2, 10, true


I've tried:

  • Removing and re-adding the account
  • Deleting oauth2.issuer and oauth2.scope in config editor and re-login
  • Adding the account in a new profile
  • Switching to basic authentication for SMTP

They don't solve the issue.

Asked by bc3104hzy 4 months ago

Last reply by bc3104hzy 1 day ago

Thunderbird Reminder will not dismiss or cancel so no access to my emails

This morning I opened Thunderbird and a Google Calendar reminder popped up. I clicked 'Dismiss' but the reminder did not disappear. I tried clicking the X close button … (read more)

This morning I opened Thunderbird and a Google Calendar reminder popped up. I clicked 'Dismiss' but the reminder did not disappear. I tried clicking the X close button but the reminder did not disappear.

The problem is that this prevents all access Thunderbird. Nothing is selectable so I have no access to my emails or to any of the Thunderbird settings.

I tried reinstalling Thunderbird (without deleting my profile) and the Google Calendar reminder pops up again.

So I am really stuck!

Can anyone help solve this issue please.

Asked by Robert Campbell 1 day ago

Local folder on NAS drive

Hi I have a company email account with a large amount of emails accessible from several computers. I created a local folder in Thunderbird on my NAS drive and directed th… (read more)

Hi I have a company email account with a large amount of emails accessible from several computers. I created a local folder in Thunderbird on my NAS drive and directed the locations to it on my computers. I have emails sorted by year, as well as received and sent. When I open the program, I can see the email subject, recipient, and date. However, I can't open any of the messages; both the quick preview and the separate window show a white background. What's the problem?

Asked by michal.bieganski 3 days ago

Last reply by michal.bieganski 1 day ago

Windows 11, Thunderbird 140, How to increase the"New Event" box and its Font

Windows 11, Thunderbird 140, How to increase the"New Event" box and its Font - Windows 10, the size is OK - I have 'Googled" this problem and there seems to be no answe… (read more)

Windows 11, Thunderbird 140, How to increase the"New Event" box and its Font

- Windows 10, the size is OK

- I have 'Googled" this problem and there seems to be no answer.

Kind regards: Gary Shaw

Asked by gary.s.shaw 2 days ago

Last reply by gary.s.shaw 1 day ago

Message Filters: triggered information + avoid duplicates

Could you please add the columns "triggered number" and\or "last triggered" to Message Filters > Rules > Match? This would good, for example, to determine which ema… (read more)

Could you please add the columns "triggered number" and\or "last triggered" to Message Filters > Rules > Match? This would good, for example, to determine which email filters are still useful (so old ones could be removed).

Also, the fields conditions really need a sort or "find duplicate" options to avoid bloating the list with copies.

Thank you

Asked by phaolo 1 day ago

Last reply by phaolo 1 day ago

lost a file in updating over old version

I was getting a message ( there is no email program associated to perform the requested action) when trying to send a scan to an email recipient. Thunderbird is set as t… (read more)

I was getting a message ( there is no email program associated to perform the requested action) when trying to send a scan to an email recipient. Thunderbird is set as the default email program app. I finally installed Thunderbird setup 139.0.2 to update Thunderbird and checked the box to keep all files but now I have lost most of the sub files in one of my folder marked Local folder, and contact list. This file was not associated with an email address but where I put important info from emails I receive. Any suggestions on how to recover his file information?

Asked by jrnr 1 day ago

Transferring folders from Outlook Classic to Thunderbird

I've decided to rid myself of Outlook Classic 2024 and switch to Thunderbird. I completed a download, familiarized myself with it, then used the 'import' tool to transfe… (read more)

I've decided to rid myself of Outlook Classic 2024 and switch to Thunderbird. I completed a download, familiarized myself with it, then used the 'import' tool to transfer my Outlook emails, contacts and folders. Although, all of my contacts and one folder (with associated sub-folders) arrived, no other folders nor my inbox, sent, trash/deleted arrived. I tried this process several times and was never able to receive any more than I did on my first attempt. Can anyone please advise me on how this can be done? - Thank you in advance for any assistance.

Asked by Placerville 1 day ago

Can not copy/paste email messages onsite bank emails.

I can not copy/paste Screen for some bank emails in Thunderbird. I get ? and Squares The page title is copied. I can copy/paste the same emails on Apple Mail and my … (read more)

I can not copy/paste Screen for some bank emails in Thunderbird. I get ? and Squares The page title is copied. I can copy/paste the same emails on Apple Mail and my Comcast server. Can you help me turn off the possible blocking on Thunderbird. Thank you John (jfcanfield@comcast.net)

Asked by kb5wv9dptf 2 days ago