All, For Cabal packages our default install locations on Windows are a bit of a mess. Firstly we do global installs by default. This used to make sense on Windows XP when everyone had admin permissions. It no longer makes sense for Vista or Windows 7. See this recent horror story from a new user: http://haskell.org/pipermail/haskell-cafe/2009-December/071310.html I've talked for a while about switching the default to per-user installs on Windows: http://hackage.haskell.org/trac/hackage/ticket/465 Now I'm not a regular Windows user so I would like some expert advice from Windows Haskell hackers. Specifically, are the default locations and layout for per-user installs OK? A related problem is that historically we tried to fudge things so that packages could be mostly relocatable by default. This is because Windows tends to make greater use of relocatable packages (giving users a choice of location at install time). There is a problem with relocatable packages that depend on libraries that contain data files: http://hackage.haskell.org/trac/hackage/ticket/466 My proposed solution for this is to not do anything special about data files for windows and use the same directory layout as on Unix. That is, change: datadir = case buildOS of Windows | hasLibs -> windowsProgramFilesDir "Haskell" | otherwise -> "$prefix" _other -> "$prefix" "share", to datadir = case buildOS of Windows -> "$prefix" _other -> "$prefix" "share", BTW, why do we not want the "share" subdir? It means currently we end up with a per-package directory at the top level containing the data files for that package. So then the per-user install locations on Windows 7 would be: prefix: C:\Users\${USER}\AppData\Roaming\cabal bindir: $prefix\bin libdir: $prefix libsubdir: $pkgid\$compiler libexecdir: $prefix\$pkgid datadir: $prefix datasubdir: $pkgid docdir: $prefix\doc\$pkgid htmldir: $docdir\html haddockdir: $htmldir Then separately I think we need explicit support for constructing prefix independent packages which could check for these issues. eg: cabal configure --prefix-independent Duncan