This article describes the Troubleshoot Mode of Thunderbird, which can be used to find and fix problems, especially if they are caused by add-ons.

What is Troubleshoot Mode and how does it work?

Troubleshoot Mode is a special mode of starting Thunderbird that can be used to find and fix problems with your installation of Thunderbird. Troubleshoot Mode will temporarily disable your add-ons and reset some custom settings in order to avoid these possible causes of problems. If you find that a certain problem with your Thunderbird installation does not happen in Troubleshoot Mode, then most likely one of your add-ons or a custom setting is causing the problem.

Starting Thunderbird in Troubleshoot Mode

If Thunderbird is not running:

Hold down the Shift key while starting Thunderbird.Hold down the option key while starting Thunderbird.From Terminal, run this command: thunderbird -safe-mode
You may need to specify the Thunderbird installation path (e.g. /usr/lib/thunderbird).

If Thunderbird is already running:

1. At the top right of the Thunderbird window, click the ≡ button.
2. Click menu Help.
3. Click Troubleshoot Mode and in the Restart in Troubleshoot Mode prompt, choose Restart. The troubleshooting mode dialog will be displayed.
4. In the Thunderbird Troubleshoot Mode dialog, click Continue in Troubleshoot Mode button.

Confirming that Troubleshoot Mode is activated

To confirm that Thunderbird is currently running in Troubleshoot Mode:

1. At the top right of the Thunderbird window, click the ≡ button.
2. Click menu Add-ons and Themes.

If Thunderbird is in Troubleshoot Mode, you will see the following banner near the top of the Add-ons Manager tab content:    (i) All add-ons have been disabled by safe mode.

Turning Troubleshoot Mode off

1. At the top right of the Thunderbird window, click the ≡ button.
2. Click menu Help
3. Click menu Turn Troubleshoot Mode Off. This will immediately close Thunderbird and restart it in normal mode.

Or you can just exit and restart Thunderbird as you normally would.