Thunderbird Community Forum

Hello, I want to delete all incoming gmail messages. I have set up a filter but instead of deleting them it puts them in the Trash folder.

Is this the expected behaviour?

I have both a "Sent" and "Sent Mail" folder; both have slightly different URLs when I check Properties ("Sent" folder shows imap://"myname"1%40gmail.com@imap.gmail.com/Sent and "Sent Mail" folder shows imap://"myname"1%40gmail.com@imap.gmail.com/%5BGmail%5D/Sent%20Mail). I don't need both of them; which one can I delete...and HOW do I delete it? Right-click doesn't have "delete" option.

I receive email fine. The website email works fine. I cannot send email via thunderbird and have not changed my settings which worked for years. my smtp account. I have rebooted my Windows 10 pc numerous times. What can do this? How can I fix this>

I suspect there is no fix and I (possibly) can restore from backups, but I would sure like to know what the issue is.

I tried retrieving an e-mail from the "folder" where I kept e-mails from 2023. The "index" one sees displayed for the folder had e-mails from Jan-Mar of 2023, but Thunderbird froze when I tried to open any of them. I tried the repair function (which I imagine is meant to rebuild the .msf file), but after than the index contained nothing from Jan-Mar. I opened both the .msf file and the no-extension file in Notepad, but I see nothing from those months.

Any clues/help would be appreciated.

In transitioning from a Windows 10 Laptop to a new Windows 11 laptop, Thunderbird reports that "Thunderbird profile cannot be loaded. It may be missing or inaccessible" I've copied three times an 11gb Profile from the W10 to the W11 laptop using a micro SD USB transfer, which seems to be successful, and the file names are identical. The copy is directly from the Explorer location under User, AppData, etc. and conforms to instructions from Thunderbird.

Although Thunderbird runs fine with multiple email accounts In the Windows 10 laptop, when I clear Cache and restart Thunderbird, I get a message: "file link provider for WebDAV Account not properly configured". I don't know what that means. Don't know if this is causing the Profile problem.

Please help if you can.

Thanks, Gary Rubin garyrubin00@gmail.com

An extremely irritating bug in Thunderbird. Don't even remember how long it has been doing this; when I am typing a message, if I so much as switch away from the Thunderbird window (to look something up for example), when I come back to the window it will switch the font size to 1-2 points smaller than what it had been doing before. I have not selected any formatting settings, and had been typing in it's default type size. Merely switching out of the window should not perform a type size change.

I have ever had to just highlight the entire message (if TB has completely fubarred the font), delete it from TB, paste it into a plain-text editor to remove all formatting, and then paste it back in.

My Thunderbird is IMAP'ed to my generic usa.net email server. It downloads everything to Thunderbird serving as backup only. I have set that local delete does not delete on the server.

It has now amassed ~200.000 emails in the active Thunderbird Inbox. (No, I don't want to delete any !:o) I want to move the ~200.000 emails to a local folder not affecting the ongoing download sync from usa.net. The local folder is to be offline.

How do I bulk move the ~200.000 emails in the active Thunderbird Inbox to a local Thunderbird folder? - not deleting anything locally or on the server - keeping the sync download from the usa.net server running onwards into the now purged Inbox - not having the sync re-download from the server (defeats my intended purpose #:o)

Microsoft Outlook Client emails are legally valid in a court of law, but Thunderbird emails are not. Can we start taking baby steps towards making Thunderbird emails a little more viable in legal applications?

While I do not understand these things in the depth required, can we start taking baby steps towards achieving legal validity of emails downloaded from Thunderbird?

I am presenting below a conversation that I had with chat GPT regarding this matter for the help of anyone who wishes to take this up.

Chat GPT:

QUESTION 1: 1. As per my limited knowledge, Outlook client emails are legally valid because the header cannot be edited. This however, is not true of Thunderbird emails. Do I understand correctly? 2. What are the challenges in making Thunderbird header not user editable, so that Thunderbird emails also have the same benefit?

Chat GPT: Your question touches on email authenticity and legal validity—especially in regulated or evidence-sensitive contexts. Let's break it down:

Is it true that Outlook headers are immutable and Thunderbird’s are not?

Partially True — but needs clarification.

Email headers in both Outlook and Thunderbird

Can be viewed by recipients, but cannot be edited after the email has been sent. Only during composition can certain headers (like `From`, `Reply-To`) be changed, depending on the setup.

What you cannot change post-sending:

After an email is sent (from any client), the core SMTP headers (`Date`, `From`, `Message-ID`, etc.) are locked. These are generated by the sending server and cryptographically traceable via server logs or DKIM.

Outlook’s extra layer:

Outlook integrates closely with Microsoft Exchange, which stores server-side logs, message tracking, and non-editable audit trails (e.g., via journaling). That’s what gives Outlook/Exchange emails more evidentiary credibility, not just the client itself. In contrast, Thunderbird usually connects via standard IMAP/SMTP, without server-side logging, unless used with a corporate mail server like Postfix + Dovecot + journaling.

In Summary: Table Feature Outlook (w/ Exchange) Thunderbird Headers editable during composition Yes (some fields) Yes (same) Headers editable after sending No No Built-in server-side logging Yes (Exchange) No (unless configured) Strong evidentiary trail Common in enterprise Requires external setup

What are the challenges in making Thunderbird headers non-editable during composition?

The challenge lies not in technical impossibility, but in the design philosophy of Thunderbird:

a. Open Source & User Control

Thunderbird is open source, so users can customize or even extend the client to manipulate headers (via extensions or config changes). This is powerful for advanced users, but not ideal in regulated or high-trust environments.

b. Lack of Server-Side Enforcement

Thunderbird relies on whatever SMTP/IMAP servers it connects to. Unless the server enforces policies (like DKIM signing, DMARC, or header filtering), client settings are only soft limits.

c. Missing Native Audit Features

Outlook/Exchange logs metadata like when a message was sent, delivered, read, etc. Thunderbird lacks that unless paired with enterprise-grade backends. How Could Thunderbird Improve Legal Trustworthiness?

1. Header Locking During Composition

  	Disable or grey out fields like `From`, `Date`, `Message-ID`.
  	Possible via extension, but not enforced by default.

2. Enforced Server-Side Signing (e.g., DKIM)

  	Ensure outgoing mail is cryptographically signed to verify integrity.
  	Requires a properly configured mail server, not just Thunderbird.

3. Journaling or BCC Archiving

  	Auto-BCC all sent mail to a tamper-proof archival system.
  	Thunderbird can do this via rules or server configuration.

4. Extension or Mode for “Forensic Compliance”

  	Custom Thunderbird modes that restrict editing headers, disable extensions, log actions, etc.

Final Thoughts

You're correct in understanding that Thunderbird offers less baked-in legal reliability than Outlook + Exchange. But this isn’t due to insecure design—rather, it's due to Thunderbird’s flexibility and lack of tight server integration. Thunderbird can be made trustworthy with the right server configuration (DKIM, archiving) and possibly some custom add-ons.

If you’re looking to build or propose a “forensic-grade” Thunderbird environment, I can help design one with proper technical constraints and audit trails. Let me know!

QUESTION 2: My legal Counsel has told me that emails downloaded from the Gmail server into the outlook client are legally valid. So even without Microsoft Exchange and all the other server side logging, Outlook emails are legally viable. Chat GPT

Yes — your legal counsel is broadly correct, and here’s the nuanced explanation:

Emails Downloaded via Outlook (from Gmail) Can Be Legally Valid

Even without Microsoft Exchange, emails downloaded into Outlook (say via IMAP or POP from Gmail) can still be legally viable evidence, because:

1. Outlook stores email in a tamper-evident format

Outlook saves emails in `.pst` or `.ost` files. These files have a structured, proprietary binary format that is hard to tamper with without detection. Courts often accept these files (with chain of custody) as original records.

2. Outlook preserves server headers

Even when connected to Gmail, Outlook does not modify or fake headers. It shows server-signed headers (like `Message-ID`, `Date`, etc.) exactly as received. These headers can be verified independently against:

Gmail’s “Show Original” → raw headers DKIM/DMARC authentication

3. Integrity from Gmail itself

Gmail assigns unique `Message-ID`s and signs outgoing mail with DKIM. DKIM proves the message has not been tampered with since it left Google’s servers. So even if Outlook is the client, the source of trust is Gmail + DKIM, not just the software.

In Legal Contexts

4. What courts typically require is:

 A copy of the original message as received (headers intact)
 Some form of chain of custody (who had access, how was it stored)
 Optionally, confirmation from the mail server logs (if challenged)
 Outlook is often used in corporate/legal environments because:

It does not let users easily forge full headers The data format is harder to manipulate Legal teams and forensic experts are familiar with `.pst` files

So even without Exchange, emails received and stored in Outlook are trusted, provided:

The full headers are intact The `.pst` or `.ost` file has not been tampered with

5. How This Differs from Thunderbird

Thunderbird also preserves headers and stores messages locally — but: Table: Aspect Outlook Thunderbird Storage format `.pst`/`.ost` (proprietary) `.mbox` or plain text Header immutability Enforced by format Editable via text file (with effort) Forensic familiarity High (in legal circles) Moderate Tamper-evidence Strong (binary format) Weak (editable with text editors)

So Thunderbird messages can technically be altered more easily after download, especially if stored in `.mbox` or `.eml` formats. That’s why they are viewed with more caution in legal settings.

Conclusion

Yes — emails downloaded into Outlook, even from Gmail, are generally accepted as legally valid, provided the headers are intact and the file has not been manipulated. Outlook's storage format and market reputation contribute to its legal trustworthiness — even without Exchange.

If you want to achieve similar legal credibility with Thunderbird, the focus should be on:

Enforcing DKIM-signing (from Gmail, already done) Locking down `.eml` or `.mbox` file access Possibly archiving in tamper-evident formats

Let me know if you’d like a workflow to export Thunderbird emails into a legally robust format similar to `.pst`.

When I use Mozilla's VPN service...many mozilla vpn servers will block me from sending out emails giving this error message:

Sending of the message failed. An error occurred while sending mail. The mail server responded: Service unavailable; Client host [23.234.88.xxx] blocked using clients.rbl.e-scout.net; host 23.234.88.xxx blocked due to abusive behavior from your network. Please contact servers@ispn.net for resolution.. Please check the message recipient "xxxxxxx@xxxxxxxxx.com" and try again.

Mosilla's VPN service is blocking its own Thunderbird software from functioning...lolol Are you going to fix this Mozilla??? Looks like you're tripping over your own feet...

All of a sudden my account will not open automatically?...asks me for my password?...I have no idea what that is...if you answer via email I cannot open it to see your answer..

When I tried to log in to my Google Email account, the authorization pop-up window that appeared was completely blank. I have tried operations such as re-logging in, but it still didn't work.

I received a request for donations for the 100th time. I have donated to the group more than once, and coincidentally, my system crashed and prompted me to make another donation. We need a permanent fix to stop the donation requests and get Thunderbird functioning properly.

Unknown to me Microsoft ditched POP3 recently. I have a large 22gb Outlook .pst file with important historical data for volunteer run non-profits. Using Outlook for 15 years or more. Outlook 2021 that was working stopped suddenly and now only uses IMAP. IMAP and 22gb chokes and is unnecessary as synchronisation not required or desired -or the expense of Microsoft Onedrive excess storage fees.

Can Thunderbird import this large .PST and can it connect to Telus in some way like it used to and that does not invoke IMAP? In other words everything local? Thanks!

I´ve used Gmail through Thunderbird for many years now, mainly because I prefer your treestructure. After changing laptop I discovered that a new map had entered the tree, which turned out to be Gmail´s map "Important" (Viktigt in Swedish). Important stores ALL incoming mail, now over 3 700! There are "only" under 400 in the Incoming map. If I erase a mail from Important it will also be erased from the Incoming map, and vice versa. Important should be for me to decide if a mail should be temporarely stowed there. Can you tell how to clean out only the Important? Best regards and thanks

I'm a long time user of TB. However, the installation I have now is fairly new on a Win 11 computer. I have attached a screen shot showing my server settings where it clearly shows that TB is not to download any messages on it's own.

I have an email address (cox.com) that was taken over by Yahoo some year and half ago. I don't remember this problem occurring on my Win 10 computer.

Why is Thunderbird downloading messages when it's not supposed to?

Thank you.