Where do the local arara rules live under windows?

See the preface of section 6 (“Configuration file”) and subsection 6.1 (“Search paths”) in the GREAT arara manual (I speak of version 3.0 here). You have to create a configuration file with the name “araraconfig.yaml” directly in %UserProfile%, and in this file you can add a path for your local rules.

%UserProfile% is:

• until Windows XP by default C:\<Documents and Settings>\<username>, where <Documents and Settings> is language dependent.
• since Windows Vista by default C:\Users\<username>. You see, the first part Users is valid for all languages, but Microsoft even so thought, it would be a good idea to provide in system’s own Windows Explorer only a translated folder name (e.g. here in German I can only see Benutzer). But on command line and in batches and cases like here for arara you need the correct folder name Users – but the best approach would consist in only using the mentioned system variable with added subfolders.