Nanoman's Company Support

These pages are intended to be referenced by customers of Nanoman's Company. Visitors are welcome to reference these pages, but our support for you may be limited.


Mozilla Thunderbird

Mozilla Thunderbird is an excellent email client that can be downloaded for free from its website:

Unfortunately, we and most of our customers dislike several of the default settings in Thunderbird. Fortunately, all these settings can be changed relatively easily.

This page contains procedures for changing Thunderbird's default configuration, and it also includes our rationale for making these changes. You may ignore our "Rationale" lines if these don't interest you, but please read every step when following these instructions, and please contact us if you find any problems.

The information on this page was written for configuring Mozilla Thunderbird version 68.9.0 as it would normally be configured by Nanoman's Company. Most of this will probably continue to apply for later versions, but your results may vary.

With the release of each new version of Thunderbird, we consider revising this page, but we don't always do so. We review this page before each large deployment, and/or when we notice problems or significant changes in Thunderbird, but we're currently unable to justify more frequent reviews/revisions.

Connection Information

Before using Thunderbird or almost any email client, you'll need to know your connection information for your incoming and outgoing email servers. If you don't know this information, then you'll need to contact your email provider, and they should be able to provide you with these details:

Incoming Email Server
SecuritySTARTTLS (or TLS)
AuthenticationSASL (or "Normal Password")
Outgoing Email Server
SecuritySTARTTLS (or TLS)
AuthenticationSASL (or "Normal Password")

Additionally, you should ask your IT provider if local caching of the email account's messages should be enabled on the computer/device that you'll be configuring. This is the default setting in Thunderbird and most other email clients, and it's intended to help improve performance while working around potential connectivity problems. There usually aren't any issues with having this enabled, and most users will want this enabled, but it can cause problems for a minority of accounts/computers/networks/organizations/users/et cetera. We haven't written a guide that describes the variables to consider when making this decision, but if you're a customer of ours who needs to know what would be best for you, then you're welcome to contact us for personalized advice.

Thunderbird Installation

The procedure for installing software on a computer can vary drastically from one computer to another. Many thousands of different computer configurations have been deployed by our company and others, so we're not going to attempt to describe how to install Thunderbird on any computer. If you don't know how to install software on your computer, then please contact your IT provider.

Nanoman's Company has installed Mozilla Thunderbird on every PC that we've deployed since Thunderbird's early versions were released in 2003. If your PC's current operating system was installed by us from 2003 to present, then unless somebody has removed it, you should already have Thunderbird installed.

Thunderbird Preferences

After Thunderbird is installed, we recommend changing several settings before using it to access email accounts. To change these settings, please follow these steps:

  1. Open Mozilla Thunderbird.
  2. If the "Set Up an Existing Email Account" window appears, click the "Cancel" button to close it.

    Rationale: By default, instead of using the generally much more efficient maildir format for local message storage, Thunderbird uses the mbox format. When an email account is connected to Thunderbird, Thunderbird can't change the format it uses for storing local copies of the account's messages. To change how Thunderbird stores local copies of a connected account's messages, you'd have to remove and reconnect the account. To avoid this extra work, don't connect the account until after you finish adjusting Thunderbird's "Preferences". Mozilla officially recommends that Thunderbird users use mbox due to problems with their maildir format, but none of these problems have affected our customers, and we've found that the benefits of Thunderbird's maildir format significantly outweigh its risks.

  3. Assuming you're not using Apple macOS, press Alt+V to open the "View" menu, and then select "Toolbars" -> "Menu Bar" to enable the menu bar.

    Rationale: It's very easy to ask a customer to access something from a menu that has a word for a name, whereas it's very tedious -- and sometimes frustrating for them -- to ask them to find Thunderbird's menu button and then navigate its submenus. Also, our customers consistently complain when they can't find the menu bar to access a function that's accessible through it, whereas we've never heard a customer say that they don't want to see Thunderbird's menu bar.

  4. At the bottom of the Thunderbird window, if you see a message asking "Would you like to help improve Mozilla Thunderbird by automatically reporting memory usage, performance, and responsiveness to Mozilla?", click the "No" button.

    Rationale: Thunderbird may attempt do this anonymously, but it adds the potential for something to go wrong.

  5. Open the "Thunderbird Preferences" screen. Where you find this depends on your operating system:
    Operating SystemLocation
    Apple macOS"Thunderbird" menu -> "Preferences"
    FreeBSD"Edit" menu -> "Preferences"
    Microsoft Windows"Tools" menu -> "Options"
    OpenBSD"Edit" menu -> "Preferences"
    TrueOS"Edit" menu -> "Preferences"
    Xubuntu"Edit" menu -> "Preferences"
  6. If you don't see the "General", "Display", "Composition", and other tabs on the left side of the "Thunderbird Preferences" screen, then maximize the Thunderbird window.

    Rationale: Thunderbird hides these tab names if the Thunderbird window is too narrow to fit both the tabs' icons and names beside each other, and Thunderbird currently won't display the names of these tabs if you hover your mouse cursor over these icons. These instructions expect you to be able to recognize tabs based on their names, so you should make the Thunderbird window sufficiently wide.

  7. Under the "General" tab, uncheck the checkbox beside "When Thunderbird launches, show the Start Page in the message area".

    Rationale: No customer has ever told us that they want to see something other than their email messages when they open Thunderbird, but we've had many customers complain when they saw a web page instead.

  8. Go to "Display" tab -> "Advanced" tab (not the "Advanced" button).
  9. Under "Open messages in", put a check in the radio checkbox beside "A new message window".

    Rationale: This is the preference of the vast majority of our customers, but it's not the only reason why we change this setting. A good default setting in Thunderbird is that it will reopen tabs that were open when Thunderbird was closed, but we've encountered several situations where customers have unwittingly had hundreds of messages open in tabs, and this has resulted in drastic performance loss. For the minority of customers who prefer opening messages in tabs, restoring this default setting is relatively easy.

  10. Go to "Composition" tab -> "Spelling".
  11. Put a check in the checkbox beside "Check spelling before sending".

    Rationale: We've had a few customers tell us that they want their messages sent without having their spelling checked beforehand, but many of our customers have told us that they really like this feature, so we enable this by default.

  12. Change "Language" from "English (United States)" to "English (Canada)".

    Rationale: Most of our customers use Canadian English primarily.

  13. Go to "Security" tab -> "Junk".
  14. Put a check in the checkbox beside "When I mark messages as junk".

    Rationale: Despite our best efforts, our customers continue to receive varying amounts of email spam, so this makes it easier for them to sort through their messages.

  15. Go to "Security" tab -> "Anti-Virus".
  16. Put a check in the checkbox beside "Allow antivirus clients to quarantine individual incoming messages".

    Rationale: If a customer uses a virus scanner, then this should help it fulfill its purpose.

  17. Go to "Attachments" tab -> "Outgoing".
  18. Uncheck the checkbox beside "Offer to share for files larger than".

    Rationale: Most of our customers don't trust "clouds".

  19. If the "Calendar" tab exists, go to "Calendar" tab -> "General", and set "Date Text Format" to "Short: YYYY-MM-DD".

    Rationale: This has been the Canadian and international standard format for the numeric representation of dates since the 1970s, and it doesn't require bilingual translations.

  20. Go to "Advanced" tab -> "Data Choices".
  21. Uncheck the checkbox beside "Enable Crash Reporter".

    Rationale: We appreciate that Thunderbird's developers want to hear about problems with their software, but we don't want to risk the possibility of any customer's private data being released.

  22. Go to "Advanced" tab -> "General".
  23. Change "Message Store Type for new accounts" from "File per folder (mbox)" to "File per message (maildir)".

    Rationale: This eliminates the need to routinely use the "Compact Folders" function, and it eliminates many related problems. This needs to be set before you connect an account to Thunderbird because Thunderbird can't change the storage type for an account's local messages after the account has been connected. Please don't skip this step.

  24. In the bottom-right corner of "Advanced" tab -> "General", click the "Config Editor" button.
  25. On the "This might void your warranty!" screen, click the "I accept the risk!" button.
  26. In the "Search" box, type "nglayout.enable_drag_images", and then double-click its Value ("true" by default) until it changes to "false".

    Rationale: This fixes an officially unsolved problem that has affected our customers.

  27. In the "Search" box, delete everything, type "", and then double-click its Value ("true" by default) until it changes to "false".

    Rationale: Our customers who use online messaging systems like IRC and XMPP have told us that they prefer using separate software like HexChat, Psi, and Pidgin, so this reduces clutter in their Thunderbird windows.

  28. Close the "about:config" screen.
  29. Close the "Thunderbird Preferences" screen.

Account Settings

Multiple email accounts can be connected to Thunderbird, and each may optionally have its own separate "Inbox", "Sent", "Trash", and other folders. For each account that you want to connect to Thunderbird, please follow these steps:

  1. Open the "Account Settings" window. Where you find this depends on your operating system:
    Operating SystemLocation
    Apple macOS"Tools" menu -> "Account Settings"
    FreeBSD"Edit" menu -> "Account Settings"
    Microsoft Windows"Tools" menu -> "Account Settings"
    OpenBSD"Edit" menu -> "Account Settings"
    TrueOS"Edit" menu -> "Account Settings"
    Xubuntu"Edit" menu -> "Account Settings"
  2. Go to "Account Actions" -> "Add Mail Account".
  3. Enter your name into the "Your name" box.
  4. Enter your email address into the "Email address" box.
  5. Enter your incoming server password into the "Password" box.
  6. Click the "Continue" button.
  7. Wait for Thunderbird to guess -- possibly incorrectly -- the settings for your incoming server and outgoing server.

    Rationale: There are ways to avoid this, and avoiding this definitely has advantages, but in most cases, it takes more time to avoid this than to wait.

  8. Click the "Manual config" button.

    Rationale: Every email account is unique, so it's best to carefully examine its connection settings before proceeding. If you don't, then you'd be much more likely to encounter problems with your account's security and/or connection.

  9. If the guessed settings don't precisely match the actual settings for your incoming and outgoing email servers, then change these settings accordingly.
  10. Click the "Advanced config" button.
  11. On the left side of the "Account Settings" window, select your email address.
  12. If your email address is being used for an organization, you should type the organization name into the "Organization" box ("Acme Widgets, Incorporated", for example).

    Rationale: This appears as the "Organization" email header, which isn't visible by default in most email clients, but some people may expect and/or require this to be set.

  13. If you have an email signature file, put a check in the checkbox beside "Attach the signature from a file instead", and then "Choose" the file. If you don't have an email signature file but do have an email signature to use, type it into the "Signature text" box.

    Rationale: For various reasons, many people need or want text known as a "signature block" added automatically to the bottom of every message they write. It's generally recommended that such text be limited to a maximum of four lines, and the inclusion of legal disclaimers is generally considered ineffective for several reasons (example: disclaimers should appear before content is presented, not after). Thunderbird will precede signature blocks with a line containing the signature delimiter string ("-- "), and this can be disabled in Thunderbird's "Config Editor" by changing the Value of "mail.identity.default.suppress_signature_separator" to "true", but we don't recommend doing so because this is intended for better interoperability with email clients that support it.

  14. Under your email address on the left side of the "Account Settings" window, select "Composition & Addressing".
  15. If you want to send messages in plain text, then uncheck the checkbox beside "Compose messages in HTML format". If not, then leave this checked.

    Rationale: Plain text is what we and some of our customers prefer, but most of our customers prefer the default setting. In the default settings for Thunderbird's "Send Options" (under "Thunderbird Preferences" screen -> "Composition" tab -> "General"), Thunderbird will attempt to send both plain text and HTML versions as a multipart message, and this works very well for the vast majority of messages, but at the cost of the message's body requiring about double the storage space and bandwidth.

  16. If you don't want to be a top-poster, then change "start my reply above the quote" to "start my reply below quote". If you want to be a top-poster, then change "below the quote (recommended)" to "below my reply (above the quote)".

    Rationale: On large mailing lists and among advanced users, using the posting style known as "top-posting" is generally discouraged. Unfortunately, despite our advocacy of superior posting styles, virtually all our customers choose to be top-posters.
    A: Because it complicates the process of reading message thread history.
    Q: Why is top-posting such a bad thing?
    A: Top-posting.
    Q: What is the most annoying thing in newsgroups and in email?

  17. Under your email address on the left side of the "Account Settings" window, select "Junk Settings".
  18. Put a check in the checkbox beside "Trust junk mail headers set by".

    Rationale: Most of our customers use SpamAssassin on their email servers, and Thunderbird uses SpamAssassin as its default option for this setting, so this helps Thunderbird sort out email spam more efficiently.

  19. Put a check in the checkbox beside "Move new junk messages to".

    Rationale: Virtually all our customers expect email spam to go to their "Junk" folders, not to their Inboxes or elsewhere.

  20. Under your email address on the left side of the "Account Settings" window, select "Synchronization & Storage".
  21. If you need/want to disable local caching of email messages, then uncheck the checkbox beside "Keep messages in all folders for this account on this computer". If not, then leave this checked.

    Rationale: Most of our customers should keep this checked, but some shouldn't. Please contact us if you're a customer of ours who needs to know which option is best for you.

  22. Click the "OK" button to close the "Account Settings" window.
  23. If you're asked if you want to save changes to the Message Synchronization settings, click the "Save" button.
  24. Under your email address on the left side of the Thunderbird window, click "Inbox".

    Rationale: This is usually a good test to see if the incoming email server connection settings work correctly.

  25. To the right of the column headers "Subject", "Correspondents", "Date", et cetera, there's a little icon that will show "Select columns to display" if you hover your mouse cursor over it. Click this icon to set these columns to display:
    • Thread
    • Starred
    • Attachments
    • Read
    • Correspondents
    • Junk Status
    • Date
    • Size

    Rationale: By default, Thunderbird has "Size" unchecked, but we believe that this should be checked by default because this helps to warn users about large messages. If a user wants to know why some messages take a long time to download and/or display, then this should help them to understand why.

  26. Click and drag the column headers to arrange them in whatever order works best for you. Going from left to right, the vast majority of our customers prefer this sequence:
    1. Thread
    2. Read
    3. Starred
    4. Date
    5. Correspondents
    6. Subject
    7. Size
    8. Attachments
    9. Junk Status
  27. To apply the message column arrangement to all your mail folders, click the "Select columns to display" icon, and then select "Apply columns to" -> "Folder and its children" -> (your email address) -> (your email address).

    Rationale: If you don't do this, then only the folder that you arranged would have this arrangement.

  28. Try writing a test message to the account's email address.

    Rationale: This should verify whether or not Thunderbird has been correctly configured to send and receive messages using this account.

Thunderbird Add-ons

Mozilla Thunderbird comes with almost all the functionality that our customers require, but it's missing some functionality that's important to some/all of our customers. Fortunately, Thunderbird has a large selection of add-ons that are able to provide this functionality.

These are some Thunderbird add-ons that we recommend considering:

We very strongly recommend this add-on. We've been installing this by default every time we've deployed or serviced Thunderbird since 2020-03-17.
Enigmail functions as an interface to an OpenPGP program named GnuPG. OpenPGP is a freely available email encryption standard, and GnuPG is open-source software that may be downloaded for free.
Starting with version 78.0, Mozilla Thunderbird will have OpenPGP functionality built-in. This means that Enigmail will no longer be required after Thunderbird version 78.0 is released.
Mozilla Lightning is a calendar and task manager that many of our customers use. We've been installing this by default every time we've deployed or serviced Thunderbird since the discontinuation of Mozilla Sunbird (a separate program with identical functionality).
LookOut (fix version)
"LookOut (fix version)" attempts to convert proprietary TNEF attachments into standard MIME attachments. Some of our customers require this, but most don't because TNEF usage is fortunately declining and widely discouraged.
A small minority of email users are using a closed-source email client that's notorious for being horribly insecure, extremely unreliable, and having severe problems with data corruption. This awful email client has been a terrible burden on the people who are still using and/or supporting it, and because it doesn't adhere to the open standards that all email clients are expected to follow, it also causes problems for the correspondents of its users. We don't want to provide the name of this excessively problematic email client because we don't want it to have any more publicity, so we'll instead refer to it as "Toxic Garbage".
One of the many problems with "Toxic Garbage" is its default method of sending attachments. While virtually every other email client released since the year 1992 has used the totally reasonable and globally adopted MIME (Multipurpose Internet Mail Extension) standard for attaching files, this horrid email client from 1997 uses a proprietary format named TNEF. TNEF has zero advantages over MIME, provides zero benefits to senders or recipients, is drastically inferior to MIME, and most email clients don't support it because it's not the Internet standard.
Unfortunately, some of our customers sometimes receive files that have been encapsulated in TNEF format by the wretched "Toxic Garbage" email client that some of their correspondents are using by force or by ignorance. Instead of seeing one or more files as standard MIME attachments, they'll see a single attachment named "winmail.dat" or "win.dat". These "winmail.dat" or "win.dat" attachments are TNEF files, and they contain the files sent by the sender.
If you ever receive a TNEF file from one of your correspondents, then we very strongly recommend that you advise them to upgrade to a better email client, or to at least reconfigure their problematic email client to attach files using MIME instead of TNEF. If they ask why, please feel free to refer them to this section of this page. We won't support "Toxic Garbage", so if they don't know how to make this change, then they'll have to either ask their IT provider for assistance, or consider getting a better IT provider.
If somebody who sent you a TNEF file is unable to resend it as a standard MIME attachment, or if you're unable to ask them to do so for some reason, then "LookOut (fix version)" might help. It's not an ideal solution, but it might be your best alternative.

Installing Thunderbird add-ons is pretty straightforward:

  1. Open Mozilla Thunderbird.
  2. Go to "Tools" menu -> "Add-ons".
  3. Go to the "Extensions" tab.
  4. In the search box beside "Find more extensions", enter the add-on's name.
  5. On the search results page, beside the add-on, click the "Add to Thunderbird" button.
  6. When asked if you want to add the add-on, click the "Add" button.
  7. Click the "OK" button to acknowledge that the add-on has been added to Thunderbird.
  8. On the search results page, if the add-on has the words "requires restart" beside it, close Mozilla Thunderbird, and then open it again.

Email Security

Sending an email message is as secure as sending a postcard. To learn what we mean by this, and to learn how to cryptographically sign and encrypt your email messages, please see our OpenPGP page.