It is not officially supported (no patches from core developers, no buildbot), but it is not officially rejected (working patches might be reviewed, and even applied). I think a request like this, with no code, should have gone to cygwin people first, and without a patch, should be closed as out of date -- how knows what the situation with cygwin and winreg is now -- or 3rd party. Simon's post suggests that there once was a 3rd party solution that might have solved Zooko's problem.