We experienced an issue with the User Profile Service Application, and had to rebuild it (by deleting the Sync DB, and re-using the Profile and Social DB's.
The service is working (importing user profiles, etc, and allowing new users to create MySites), but existing users with MySites are unable to access their content. The error that is presented is: "Your personal site cannot be created because a site already exists with your username. Contact your site administrator for more information."
The MySite site collections DO show up in Central Admin. Deleting the MySites is not a viable option.
The diagnostic logs state that that there is a user name conflict. Makes sense, the site already exists. How do I get SharePoint to sync up with the user profile service? Running a UPS sync hasn't fixed the issue. I've looked at the PowerShell cmdlets for the service application, but don't see anything that would immediately help.