mssql-conf set-sa-password doesn't work if the sa account has been renamed

[bluecreature]

Hello,

Found a small issue with mssql-conf which I thought I'd let you know:

If the "sa" account has been renamed to something else via "ALTER LOGIN", then "mssql-conf set-sa-password" doesn't actually reset its password.

This is what I did in detail, in case I'm doing something wrong:

1. Running in docker, docker run -it --rm --entrypoint /bin/bash mcr.microsoft.com/mssql/server:2025-latest . The same is reproducible with 2022, too.
2. Run /opt/mssql/bin/sqlservr once to setup with MSSQL_SA_PASSWORD="<password 1>"
3. Via /opt/mssql-tools18/bin/sqlcmd -S 127.0.0.1 -U sa -P '<password-1>' -C :

ALTER LOGIN sa WITH name = superuser;
GO
exit

4. Verify I can actually login as "superuser" : /opt/mssql-tools18/bin/sqlcmd -S 127.0.0.1 -U sa -P '<password-1>' -C
5. Stop the server, then do MSSQL_SA_PASSWORD='<password-2>' /opt/mssql/bin/mssql-conf set-sa-password

<snip>
The system administrator password has been changed.

6. Start the server again (/opt/mssql/bin/sqlservr 2>&1 1>testme.log &)
7. Try to login with the new password

mssql@8a233b783aba:/var/opt/mssql$ /opt/mssql-tools18/bin/sqlcmd -S 127.0.0.1 -U superuser -P '<password-2>' -C
Sqlcmd: Error: Microsoft ODBC Driver 18 for SQL Server : Login failed for user 'superuser'..

mssql@8a233b783aba:/var/opt/mssql$ /opt/mssql-tools18/bin/sqlcmd -S 127.0.0.1 -U superuser -P '<password-1>' -C
1> ^D

[amitkh-msft]

Thank you for sharing this, we will add this to our backlog and update you accordingly. Appreciate you sharing a feedback. This looks to be an issue where we should display right message instead of stating the system admin password has changed. We will work on this.