11.7. Enigmail seems not to work with Gpg4win. What's wrong?

Gpg4win versions 1.1.0 and 1.1.1 contain an error that prevents Enigmail working with it. However, there is an easy workaround.
Assuming that you choose the default installation directory for Gpg4win, go to OpenPGP → Preferences, tick the checkbox Override with, and enter the following path: C:\Program Files\GNU\GnuPG\gpg.exe.
(Depending on your localisation of Windows, your Program Files folder may be called Programmi, Programmes, or other instead.)

The problem is that Gpg4win creates a wrong entry in the PATH environment variable.
Alternatively, instead of the workaround above, it is also possible to change the PATH such that \pub is removed from C:\Program Files\GNU\GnuPG\pub.