Error: A user already exists for the username

Error

When creating a user, the following error is displayed

A user already exists for the user name specified. Please register again using a different user name

The customer searches for the created users and the username is not listed.  

Root cause 

The username is already registered in some of the Database tables. 

Resolution

1. Open the SQL Console.
2. Validate that the user is not duplicated on the Users table by running the following query.
   
   

   Select * from users where username='<user name>'

   
   Replace <user name> with the username that you want to create. 
3. Validate that the user is not duplicated on the aspnet_Users table by running the following query. 
   
   

   select * from aspnet_Users where UserName='<user name>'

   
   Replace <user name> with the username that you want to create. 
4. Validate that the user is not duplicated on the aspnet_Membership table by running this query
   
   

   Select * from aspnet_Membership where Email='<user email>'

   
   Replace <user email> with the user email that you want to create. 
5. If there is an output on any of the queries; Delete those entries from the Database using one of the following queries, accordingly. 
   
   Note: Back up the affected tables before running the delete queries. 
   
   
   • If there is an output from the step 2 query, run this query. 
     
     

     delete from users where username='<user name>'

     Replace <user name> with the user name that you want to create.
   • If there is an output from the step 3 query, run this query.
      
     

     delete from aspnet_Users where username='<user name>'

     
     Replace <user name> with the user name that you want to create.
   • If there is an output from the step 4 query, run this query.
     
     

     delete from aspnet_Membership where Email='<user email>'

     Replace <user name> with the user name that you want to create.
6. Try to create the user again.