How to fix System.InvalidOperationException: Scheme already exists: Identity.Application

This post shows you how to solve 'System.InvalidOperationException: Scheme already exists: Identity.Application' after identity scaffolding in ASP.NET Core.

For example

Creating an ApplicationUser class that extends the IdentityUser class, then add a FullName property

public class ApplicationUser : IdentityUser
    public string FullName { get; set; }

Opening your Startup class, then modify your class as shown below.

services.AddIdentity<ApplicationUser, IdentityRole>()