There are developers using Maven which decide, for some reason or another, not to use a repository manager. As time progresses on they realize they need something more robust in order to manage all there releases, or possibly the team begins to grow in size. No matter the reason, there are times when a local Maven repo needs to be converted to a managed repo.
Stuart McCulloch ran into this as well and wrote a blog post on how to accomplish this. One caveat is the scripts expect the machine to be a Linux flavor, I guess if you had Cygwin installed then this would still work on Windows (albeit I haven’t tried).
Now with the latest release (22.214.171.124 at the time of writing) Sonatype’s Nexus Repository Manager comes prepackaged with a set of tools. One of which is a repository converter tool. Refer to the user story for more information.