Config Editor

You may sometimes need to view or edit Thunderbird preference settings, which are not accessible through the normal user interface. You can use Thunderbird's Config Editor to do this.

To access the Config Editor, go to Fx57Menu and select SettingsPreferences. Search for config and click on the Config Editor button when it is displayed.

Warning on Config editor window

Clicking on the Show All button in the display will show all hidden preferences in a tab called Advanced Preferences.

Image of typical config editor tab

In the Config Editor, you can type a string in the field showing Search preference name to filter the list of preferences to only those that contain the specified string in their names.

Note: Preferences that have been changed from their default values are shown in bold. There is a revert arrow on the end of the entry to revert the setting to the default value Config Editor RevertIcon

To edit a boolean preference (true/false value), click on the Toggle Config Editor Toggle button. For text preferences, double-clicking on the preference will enable in-place editing. Once the edit is complete, save your changes by clicking the checkmark Config Editor Save Checkmark

In rare cases, you may need to add a new preference. You shouldn't normally need to do this unless you are instructed to do so by documentation for Thunderbird or one of its add-ons.

To add a new preference:

  1. Type or paste the preference name into the search box.
  2. Select the appropriate preference type (number, string or boolean) from the offered options.
  3. Click on the Add Config Editor Add to add the preference.

To delete a previously added preference, click the trash icon following the entry Copnfig Editor Trash Icon

Modifications to preferences happen immediately. However, some parts of Thunderbird or many add-ons only read their preferences on start-up, so it is good practice to restart Thunderbird after editing preferences for your changes to take effect. It is also important to know that when you restore a preference to its default value, Thunderbird does not store that preference in the preferences file. It is only non-default preferences that are stored.

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