Fix slowness, crashing, error messages and other problems
Troubleshoot error messages on Thunderbird.
Microsoft OAuth Authentication and Thunderbird in 2024
Changes to OAuth authentication for Microsoft 365 (formerly Office 365; often abbreviated as “o365”) business and academic hosted email accounts and services.
Last updated: 02/07/2024
Mozilla Crash Reporter TB
The Mozilla Crash Reporter dialog box appears when Thunderbird crashes and lets you send a crash report. Learn how it works and how to access your crash reports.
Last updated: 04/30/2023
Profiles - Where Thunderbird stores your messages and other user data
Thunderbird saves personal information such as messages, passwords and user preferences in a set of files called a "profile".
Last updated: 12/20/2023
Rebuilding the Global Database
Rebuilding the Global Database will initiate a re-indexing of emails and address book cards (newsgroup messages are not indexed).
Last updated: 08/28/2018
Cannot receive messages
If you cannot receive messages, this page provides a series of steps you can use to check for common problems.
Last updated: 12/28/2023
Troubleshoot Mode Thunderbird
How to use Thunderbird's Troubleshoot Mode to find and fix problems, especially if they are caused by add-ons.
Last updated: 11/24/2023
Cannot send messages
If you cannot send messages with Thunderbird, this page provides a series of steps you can follow to check for common problems.
Last updated: 12/28/2023
FAQ Changing IMAP to POP
If your mail server supports both IMAP and POP, Thunderbird will use IMAP by default. Use these instructions to manually configure a POP account.
Last updated: 07/17/2018
Cannot delete messages
This article explains how to fix issues with message deletion caused by a missing or corrupted trash folder.
Last updated: 07/14/2017
Hyperlinks in Messages Not Working
When clicking hyperlinks in email, your default web browser should open and display their content. Learn why that may fail and why links may not be clickable.
Last updated: 10/07/2021
Unable to use profile when you launch an older version of Thunderbird
You have launched an older version of Thunderbird
Last updated: 10/19/2020
Sending and Receiving Messages on Thunderbird
How to send and receive email messages using Thunderbird.
Last updated: 01/09/2024
Compacting folders - Potential complications
Help the user understand some of the things that may go wrong when compacting.
Last updated: 05/12/2021
Inbox or Other Folder Full
Created: 02/13/2014
Rebuilding Global Database
Created: 02/13/2014
How can I avoid to reach the "over quota" limits of my mail server?
Created: 02/13/2014
Profiling Thunderbird Performance
How to create a Thunderbird performance profile to find causes of high CPU load or slowness.
Last updated: 03/02/2024
userChrome.css and .js and userContent are unsupported
userChrome.css, userChrome.js, userContent.css and userContent.js are unsupported because they can break at any time and are difficult to troubleshoot.
Last updated: 3 weeks, 3 days ago
