SQL Server Error : 15025, Severity: 16. The server principal ‘%s’ already exists

SQL Server Error : 15025 Details

SQL Server Error: 15025
Severity: 16
Event Logged or not: No
Description:
The server principal ‘%s’ already exists.
Severity 16 Description:
Indicates general errors that can be corrected by the user.

Reading sql server error log location from SQL Query

Identifying SQL Server Error Log File for SQL Server Error 15025, used by SQL Server Database Engine can be done by reading SQL Server Error Logs. DBA can execute the XP_READERRORLOG extended stored procedure to read the SQL Server Error Log and search for its location used by the instance of SQL Server.

USE master
Go
xp_readerrorlog 0, 1, N'Logging SQL Server messages in file', NULL, NULL, N'asc'
Go

 

For other ways to read and find error log location please our articile https://sqlserver-dba.co.uk/error-log/sql-server-identify-location-of-the-sql-server-error-log-file.html

Solution for Resolving the Error

When we move a database from one server to another that is backup and restore or detach and attach a database, the mapping between SQL logins and users always get out of sync. This is because the connection between server and database is by SID, not by name.

Assuming that the user and login names are supposed to be identical, a quick way to resolve this is to run this script:

SELECT 'ALTER USER ' + quotename(name) +
' WITH LOGIN = ' + quotename(name)
FROM sys.database_principals dp
WHERE suser_sname(SID) <> name
AND name <> 'dbo'
AND type = 'S'

And then copy the results into a query window and run it.

If the database is owned by someone else than SA(sysadmin), it is a good idea to change ownership to SA(sysadmin) and back. This is the solution for SQL Server Error 15025

SQL Server Error Code and solution summary

SQL Server Error: SQL Server Error 15025 
Severity: 16
Event Logged or not: No
Description:
The server principal ‘%s’ already exists.

Map the user logins to server logins by running script to identity and map the user logins as described above.