The user manual specifies that the following:
Microsoft Windows The global darcs directory is marked with environment
variable USERPROFILE/ and typically is C:/Documents And
Settings/user/Application Data/darcs
directory. This folder contains the cache, as well as all the per-user
settings files:
preferences, boring etc... These will became the new defaults that can be
overridden
on per-repository basis.

At least under VISTA, this is not correct, it seems this is stored
under %APPDATA%\darcs

Attachments

• unnamed

The following patch updated the status of issue1432 to be resolved:

* Resolve issue1432: refer to %APPDATA%, not %USERPROFILE%. 
Ignore-this: 2836bb1f24104a8e2347f7c755847c75
See also http://haskell.org/ghc/docs/latest/html/libraries/directory/
System-Directory.html#v%3AgetAppUserDataDirectory