3.5 Where do I put my init file?

On Windows, the .emacs file may be called _emacs for backward compatibility with DOS and FAT filesystems where filenames could not start with a dot. Some users prefer to continue using such a name due to historical problems various Windows tools had in the past with file names that begin with a dot. The init file may also be called .emacs.d/init.el. Many of the other files that are created by Lisp packages are stored in the .emacs.d directory too, which keeps all your Emacs related files in one place.

All the files mentioned above should go in your HOME directory. The HOME directory is determined by following the steps below:

1. If the environment variable HOME is set, use the directory it indicates.
2. If the registry entry HKCU\SOFTWARE\GNU\Emacs\HOME is set, use the directory it indicates.
3. If the registry entry HKLM\SOFTWARE\GNU\Emacs\HOME is set, use the directory it indicates. Not recommended, as it results in users sharing the same HOME directory.
4. If C:\.emacs exists, then use C:/. This is for backward compatibility, as previous versions defaulted to C:/ if HOME was not set.
5. Use the user’s AppData directory, usually a directory called AppData under the user’s profile directory, the location of which varies according to Windows version and whether the computer is part of a domain.

Within Emacs, ~ at the beginning of a file name is expanded to your HOME directory, so you can always find your .emacs file by typing the command C-x C-f ~/.emacs.