Multisite user syncs

Hi just joined this site, was wondering if you had a solution...

I have a multisite..

I am truly struggling to find a solution that syncs users and user roles irrespective of whether a user registers (and confirms email from pending to subscriber) on either main site or subsite. I would want the user to be autosynced from one to the other.

I would have thought this would be a basic feature of a WordPress subsite but no plugin o solution can be found! Please help! Thanks