This is an edited version of Monterail Full Dark - getting rid of the grey header and making everything dark. Just intall the .xpi file into Thunderbird

Monterail Full Dark, a Thunderbird theme inspired by the mockup of Monterail

Unfortunately this version of Thundebird (v68) broke this and a lot more of themes and unfortunately it is not easy, nor possible, to update and adjust this theme at this moment, because the so called "full themes" are no more supported.

For this reason the theme is been converted to a legacy extension, and for now it's working.

This is a full theme for the Thunderbird e-mail client, inspired by Monterail mockup and by spymastermatt's dark theme. As opposed to the spymastermatt's version, this theme can be installed easily and quickly with an addon and it's compatible with Thunderbird 60.x and 68.

The first step is to download the theme, unzip the contents and re-create a zip only with the content of "monterail-fulldark" folder. Change the extension of the archive to ".xpi". An extensive guide for install the xpi file can be found here on the Mozilla support site, starting from "A slightly less ideal case". The Addon Manager can be found by clicking the menu icon (on the right, next to the search bar) followed by Add-ons and click on the Themes panel on the left.

The theme can be directly downloaded from the Thunderbird Add-on market, the old version can be found by searching "Monterail Full Dark" directly in the add-on page of thunderbird or there, the new version can be found by searching "Monterail Full Dark 2.0 for TB>68" directly in the add-on page of thunderbird or there.

• Installation fail/Theme didn't change in Thunderbird 60
  This seems a know issue of Thunderbird 60 [1] [2]. With this workaround it'll work:

  1. Go where your application data are stored, they usually can be found in:
  • Windows: C:\Users\[your windows user]\AppData\Roaming\Thunderbird\Profiles\[(literally) random letters and numbers].default/
  • Linux: /home/[your linux user]/.thunderbird/[(literally) random letters and numbers].default/
  • MacOS: /home/[your macos user]/Library/Thunderbird/Profiles/[(literally) random letters and numbers].default/
  2. Go to the "extensions" folder, here there should be a file named "[email protected]"
  3. While Thunderbird is opened in background, delete the "[email protected]" file.
  4. Restart Thunderbird and reinstall the theme
  5. Restart Thunderbird again, the theme now should work

• The original Monterail version will be released?

Nope, it already exists: Monterail by Paenglab.

• This theme works with Windows/Linux/MacOS?

Yes. Currently the theme has been tested only on Windows 10 and openSUSE. You are free to open an issue here on GitHub if you find bugs.

• With which versions of Thunderbird can I use this theme?

Version 1.1.6 works with Thunderbird <=60.x. The latest versions (>=2.0) works only with Thunderbird >=68.

This addon is based on Monterail by Paenglab, source code is included.

Special thanks to spymastermatt for the work that he done to create the original dark theme.