Checking for new messages in other folders - Thunderbird

From MozillaZine Knowledge Base



You can only check for new messages in the Inbox folder on a POP server. However, some webmail add-ons can be configured to check for new mail in other folders. Any of those messages are downloaded to the inbox and a special header added so that a message filter can test what folder they came from.


Thunderbird for IMAP accounts by default only checks Inbox for new mail. But you can configure Thunderbird to automatically check for new messages in other folders. There are two ways to do this but NOTE: adding more folders may affect Thunderbird and/or server performance:

  • Right-click on remote folder, select Properties, and check the box for "Check this folder for new messages". If you need to do this for many folders, either install the FolderCheck addon (it adds "Check this folder for new messages" to the folders context menu), or do the following...
  • Set mail.check_all_imap_folders_for_new to true to make Thunderbird check every remote folder for new mail. The downside is there is no way to exclude a specific folder (such as a junk mail folder). (Versions after TB 5.0 replaced the global preference with server-specific ones, thus modify mail.server.default.check_all_folders_for_new instead to make it effective for all accounts with modify this preference using the Config Editor.

You may want to also use the checkmark for "Tools → Options → Advanced → Show expanded columns in the folder pane" and then click on "Unread" and/or "Total" in the small column control at the upper right corner of the folder pane.

And if you don't like Thunderbird's default visualization of folders with new mail, you may do the following to the userChrome.css file in the chrome directory in the profile to make it easier to see which folders have new mail:

/* Turn the font red and bold if folder has unread mail */
treechildren:-moz-tree-cell-text(hasUnreadMessages-true) {
color: red !important;

If you are the admin for the IMAP server you may be able to configure it to check for new mail in all folders and notify the email client using the IDLE command. For example you could do this with a Courier IMAP server by setting IMAP_CHECK_ALL_FOLDERS=1 and IMAP_ENHANCEDIDLE=1 in the IMAPD file and installing the File Alteration Monitor (FAM) package. This would effect every email client using that IMAP server regardless of whether or not the user wanted to check all folders.

If Thunderbird doesn't recognize that a folder contains unread messages try setting mail.imap.use_status_for_biff true. It causes Thunderbird to explicitly select each folder to update the message summaries, rather than using the STATUS command. It has more overhead, but some IMAP servers don't return STATUS correctly.


The Advanced Folder View list box on top of the folder pane defaults to "All Folders". It can be set to "Unread Folders" using the left or right arrows. This will display only folders that Thunderbird knows has new messages. It "knows" about any new messages stored in POP accounts or Local Folders, any remote folders that you've opened, and any remote folders that its configured to check for new mail in that folder. It doesn't know about any new messages in webmail folders unless you used a webmail add-on and checking for new mail downloaded them to the Inbox folder.

You could also create a virtual folder using saved search that tests [Status] [is] [New] for all of the folders you're interested in. It can test folders across multiple accounts, and is displayed with a special icon in the folder pane. You could also have it test [Status] [isn't] [Read] - not all unread messages are necessarily new messages.

See also

External links

  • Folder Check extension tries to make it easier to check for new mail in many folders.
  • MailBox Alert extension lets you specify for each folder a sound, system command or message when new mail is detected in that folder.
  • Sync On Arrival extension