Enigmail is not compatible with Firefox?

[patrick]

Enigmail is an extension for Thunderbird and the mail client of Seamonkey, it cannot be installed in Firefox.

Follow these steps in order to install Enigmail in Thunderbird:

1. Download Enigmail with Firefox using the context menu (right mouse click) -> Save As ...
2. Open Thunderbird and go to Tools -> Extensions
3. Click on the Install button and select Enigmail
4. Restart Thunderbird

If you are looking for a GnuPG extension for Firefox (e.g. to read web mail), then check the FireGPG extension.