Using FastMail with Mozilla Thunderbird

Note: If you already know how to set up your client, and you already understand the information below, see this help page for the server information you need to set up your e-mail client. The Troubleshooting Issues section at the bottom of this page may be helpful if you have problems.

In order to use Mozilla Thunderbird with FastMail, you'll need to enter the following information:

  • username - When you signed up for FastMail, you chose a username which is also your e-mail address. You must use the full username, including the name and the domain part, which is the part after the '@' symbol. For example, a user named John Doe might have chosen a username of "". Make sure that you specify your username in lowercase only.
  • password - When you signed up for FastMail, you chose a password to go along with your username. You will need the password to access your account. The password also keeps others from being able to access your e-mail. Your password is case sensitive, so be sure that you type it in correctly. "PASS123" is different to  "pass123". Often, users forget about the CapsLock button and mistype their password.
  • incoming mail server (IMAP or POP) - This is the server that you get your e-mail from. Internet Message Access Protocol (IMAP) and Post Office Protocol (POP) are retrieval methods used to move e-mail messages from the server to your e-mail client so that you can read your messages. POP access is not available for all service levels, please check the pricing table for details. Secure Sockets Layer (SSL) is required for your protection as well. SSL keeps people from reading your e-mail as it is transmitted between the e-mail server and your computer.
  • outgoing mail server (SMTP) - This is the server that sends your e-mail. Simple Mail Transfer Protocol (SMTP) is the method that your client uses to move e-mail messages from your client to the server so that it can send your messages. The FastMail SMTP server is not available for all service levels, please check the pricing table for details. If your service level does not allow use of the FastMail SMTP server, you must use the SMTP server provided by your Internet Service Provider (ISP).

    The FastMail SMTP server requires SMTP Authentication. This keeps people who are not users of the FastMail service from using the SMTP server to send spam messages on the Internet. SSL is required for the FastMail SMTP server. If you don't use the FastMail SMTP server, you may have different options or requirements. You will need to get that information from your ISP.

Note that these screenshots and instructions are based on Windows but the same procedure works for Thunderbird on Linux too, the only slight difference being that the 'Account Settings' option can be found under the 'Edit' menu not the 'Tools' menu.

Original text by Terence Kearns. Updated text and screenshots for Thunderbird 1.5 by Bob Peers.

View flash demonstrations.

You can see two flash demonstrations showing how to set up your account in Mozilla Thunderbird. It's probably a good idea to read through the rest of this page first to get a better idea of the process before seeing the movies.

Adding the account (794Kb)
Subscribing/Copying-Folders (703Kb)

Tutorial - Adding your account

The following tutorial has been set up using Thunderbird version 1.5. Setting up Thunderbird is a little more complex than some other clients, and the procedure has been divided into 3 sections.

Add new Account wizard

  1. Launch Thunderbird and select 'Account settings' from the 'Tools' menu.

    Thunderbird: Account settings

  2. Click the 'Add Account...' button near the lower left of the panel. This brings up the 'Account Wizard' shown below. Ensure 'Email account' is checked and then click 'Next>'

    Account Wizard with "Email account&quo;" selected.

  3. On the 'Identity' panel, enter the name you want displayed when recipients receive email from you. You must also enter your username/email address as described at the top of this document in the lower field. Click 'Next>'

    Account Wizard: Identity

  4. In the 'Server Information' panel, check the 'IMAP' radio button. Enter '' in the 'Incoming Server' field and enter' in the 'Outgoing Server' field.

    Account Wizard: Server Information

    Important: Not all service levels provide access to the '' SMTP server. Check the pricing table to see if your service level provides access. If not, you should instead set the 'Outgoing Server' field to your ISP's SMTP server. You should be able to find this information in your ISP's documentation; we don't have the information, so please don't email us asking what it is. Also, depending on the strictness of your ISP, you may also need to set the 'E-mail Address' field to your ISP's email address. The only way to be sure of if this is required or not is to try and send an email, and if you get an error, try again after changing to your ISP's email address. Finally, you should make sure that the 'Use name and password' checkbox displayed in step 1 of 'Outgoing Server (SMTP) issues' below is NOT checked.

  5. Enter the username/email address you use to access your FastMail account. Click 'Next>'

    Account Wizard: User Name

  6. Enter a descriptive name that Thunderbird will use to identify this account to you. Click 'Next>'

    Account Wizard: Account Name

  7. Verify all the details are correct. If you got something wrong, use the '<Back' button to return to that setting and keep clicking 'Next>' until you're back at this panel.

    Click 'Finish' to return back to the main settings panel.

    Account Wizard: Congratulations

  8. While in the settings panel, click on 'Server settings'. You can take advantage of FastMail's secure delivery capability by clicking 'Use secure connection (SSL)'.

    This will help to ensure that your sensitive login information (including your password) is kept a secret while it travels through unknown territory on it's way from FastMail's server to your computer. This is especially important if you've set Thunderbird to check for new mail at regular intervals.

    Account Wizard: Congratulations

    BE A GOOD NETIZEN: If you do choose to have your mailbox checked at regular intervals, then please change the default setting (10 minutes) to something more reasonable (more minutes) in case you leave Thunderbird running while you go out on vacation ;-)

    I'm sure I don't need to spell out the problems it could cause for the nice people at FastMail if lots of people left Thunderbird to check for mail every 10 minutes. You could also end up with a bigger bill from your ISP for Internet traffic.

    You will get instant notifications of new mail since Thunderbird supports the IDLE command, however you should set this interval to just under 30 (say 28 for example) minutes since FastMails IMAP server will disconnect you after 30 minutes with no activity. Checking for mail just prior to this timeout will prevent disconnections.

    Click 'OK' on the settings panel to return to the main Thunderbird screen.


And now for the tricky parts... Subscribing/Copying-Folders

Having done this much, you may be able to view mail in your inbox, but you may get error messages when sending mail, saving drafts, or deleting items to the Trash.

This is because Thunderbird doesn't know where to find your FastMail IMAP "folders" yet. These folders are set up in your FastMail account (See this FAQ for more info). They include the following preset folders by default:

  • 'Drafts': (for unfinished messages - See known issues for problems with Thunderbird saving Drafts to an IMAP account)
  • 'Sent Items': (where outgoing messages are copied/archived)
  • 'Trash': (where deleted messages go initially)

To use IMAP effectively with your FastMail folders on the FastMail server, you may need to register these (and other) remote folders with Thunderbird by "Subscribing" to them. By default, Thunderbird should search for and subscribe to all your folders once you've finished setting up your account. But you should check just in case. It doesn't hurt to be aware of what's going on either - just in case a new folder you created on the FastMail website refuses to show up in Thunderbird.

  1. From the main Thunderbird window, right-click on your new FastMail account to bring up a pop-up menu where you must select 'Subscribe...'

    Subscribe pop-up

    You should be presented with a screen similar to the following:

    Folder subscription panel

  2. Make sure you expand any subfolders you may have by clicking on the 'plus' signs.

    If you do have any subfolders, you will likely find that Thunderbird has neglected to subscribe to these automatically. You can tell because the checkbox on the right of the folder name is not checked.

    Make sure you put a check next to all the folders you want showing up in Thunderbird. This will necessarily include 'Drafts', 'Sent Items', and 'Trash' folders if you are to succeed in the next step.

  3. From the main Thunderbird window, open 'Account Settings' from the 'Tools' menu. Choose your new FastMail account and click the 'Server Settings' subgroup. Click on the 'Advanced' button (lower-right of the form).

    You should be presented with a dialog as shown below.
  4. Folder subscription panel

  5. In the field marked 'IMAP server directory' (at the TOP of the form), enter 'INBOX.' (without the single quotation marks, and *with* a period at the end -- the period is very important). Make sure the 'Server supports sub-folders...' and 'Allow server to override...' options are checked. Note that the 'Personal Namespace' should already be set to "INBOX.", with the double quotation marks. This is normal and correct.

    Click 'OK' to accept your changes and close the 'Advanced' submenu.

  6. Bring up the 'Account Settings' panel by selecting 'Account Settings' from the 'Tools' menu.

    Go to the 'Copies & Folders' panel and select 'Other' in the 'When sending messages, automatically: Place a copy in:' section.

    As per the screenshot below, select your remote FastMail 'Sent Items' folder.

    The 'Drafts' and 'Templates' settings can be left as is since they are the default names used by FastMail.

    Note that the 'Templates' folder is not created by default, if you want to use this feature you will have to create one yourself. See this FAQ entry for a description of Drafts and Templates.

    selecting your remote Sent Items folder.

That should be about it. I've included another section in case you have problems sending email. Hopefully you won't need it. Happy IMAPing :-)


Outgoing Server (SMTP) issues

Note: Guest users (free account) do not have access to the '' SMTP server. Member, Full and Enhanced users do have access to the '' SMTP server, so the following does not apply to guests. Guest users should instead set the 'Outgoing Server' field to your ISP's SMTP server. You should be able to find this information in your ISP's documentation, we don't have the information, so please don't email us asking what it is.

The way Thunderbird handles multiple accounts and multiple SMTP servers can be confusing to say the least. Remember when you specified a server in the 'Outgoing Server:' field of the 'Account setup wizard'? Well, that information is permanently set with that account. If you have a problem with outgoing mail or you already have an outgoing SMTP server setup, then you need to do 2 things:

  1. Using the information provided during the account setup there will already be a default smtp server setup for you.

    Select 'Account settings' from the 'Tools' menu and click on 'Outgoing Server (SMTP)' to open the dialog shown below.

    Outgoing server settings

    Select the entry and click 'Edit' to setup your default outgoing mail server (which may be used by any account you register with Thunderbird) as shown below.

    The description field can be set to anything you like to identify the account. You must explicitly check the 'Use name and password' box and put your FastMail login name in the 'User name:' field. You will get a strange error when sending emails if you don't do this.

    FastMail supports a secure connection capability so you may as well take advantage of it by selecting 'SSL'.

  2. The other thing you need to do is to point your new FastMail profile to the default outgoing server you just set up.

    Bring up your account settings and select 'Use default server' from the drop down list at the bottom.

    Click 'OK' to finish.


Thunderbird takes a bit of effort to set up with remote IMAP folders but it's really worth it.

If you still have problems, the people on the discussion forums over at are really helpful.

If you have a problem with Thunderbird not specific to FastMail you could also try the Mozilla Thunderbird FAQ or Thunderbird Help.


Learning more about IMAP

IMAP is a powerful protocol that allows you keep to your email synchronised, whether you're at home, at work, at a friends place or an internet cafe. You don't have to worry about what computer the email is on, because all the email is kept on the server and each client sees the same 'view' of the email. See this FAQ page to learn more about IMAP

Known Issues

  • Thunderbird does not correctly save Drafts to an IMAP account. If you save a draft using Thunderbird to your FastMail drafts folder and later edit it using Thunderbird it will work as expected. However if you save a draft to FastMail and then open it with another email client or the web interface then it will open a normal message view window and you will not be able to edit the draft.

    This is NOT a bug with FastMail but a bug with the way Thunderbird saves drafts, see the Bugzilla report for more information.

  • By default Thunderbird downloads attachments in 'chunks' which for most people means that large downloads will take a very long time to download. For a fuller description of the problem and a partial fix for this issue see this blog post.

Troubleshooting Issues

  1. When trying to send a message the mail gets sent, but you get an error of the form:
    The current command did not succeed. The mailserver responded:
    Permission denied.

    This error can occur if you haven't correctly setup the 'Sent Items' and 'Trash' folders. Please see point 5 in the section above "And now for the tricky parts - Subscribing/Copying-Folders" and make sure you follow all the steps.

    Some users have reported that regardless of what they set, this problem still occurs. A workaround for this is to configure Thunderbird to Bcc all outgoing emails to your account to have them filed into your Sent Items folder. You can do this by going to Edit/Tools, Account settings, Copies and folders, and enable the box Bcc these email addresses and enter yourusername+sentitems@yourdomain.told

  2. Cannot copy/move multiple selected messages to a different folder.

    Netscape 7.0 seems to have problems copying/moving multiple selected messages to a different folder. However, this is not an issue with Netscape 7.1.


Bob Peers

Last modified on: Mon Jan 2 18:00:00 UTC 2006