Mercurial.ini -- home of mercurial's config

(or on non-windows machines, your .hgrc file.)

Your mercurial.ini file is located here:

%userprofile%\mercurial.ini

(If you don't have a file at %userprofile%\mercurial.ini then create one now)

In powershell, you would edit:

$env:userprofile\mercurial.ini

(In recent versions of mercurial) You can edit it with this command:

hg config --edit

To edit the config of a single repo, look for the .hg\hgrc file.

When running powershell as an admin you may not have a $env:userprofile at all. If you're intending to run mercurial as a non-admin this is not an issue. Just restart powershell as a mortal user.