Question

After renaming the computer, SQL server windows authentication fails, saying OldPC\user1 couldn’t be authenticated. Rather it should look for NewPC\user1. How to resolve the issue ?

I read this SO quest. The accepted solution suggested here, say to stop SQL server instance as below –

But for me Sql server Configuration displays this error –

Answer 1

An alternative that doesn’t require restarting the service, starting in single user mode, etc. is to use PSExec from SysInternals (well, Microsoft now). You can run this to launch SSMS:

PsExec -s -i "C:\Program Files (x86)\...\ssms.exe"
--------^ s = "system"

You will be prompted to connect. The authentication method will be Windows auth, and the username will be hard-coded to NT AUTHORITY\SYSTEM. Once connected, you will be able to go into security and fix the sa password, add yourself as admin, add other admins, etc.

The following article has more details and several caveats you should read before trying this. You may also want to review the comments at the bottom:

• Recover access to a SQL Server instance

Of course after you’ve changed the underlying server name you probably want to restart anyway, after issuing the following:

EXEC sp_dropserver N'OldPC';
GO
EXEC sp_addserver N'NewPC', LOCAL;
GO

Also, if you’ve hard-coded the SQL Server service to start as a local user, say OldPC\user1, and you’ve renamed the server, you’ll also want to fix that in the properties of the service. Right-click in SQL Server Configuration Manager, hit Properties, move to the Log On tab, fix the user name / password, hit Apply, say yes to the prompt about restarting the service, and restart the service.

But you shouldn’t need to use single-user mode, which essentially requires you to restart twice.

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One way to avoid this problem: leave your machine name as OldPC. Or decide on the final name of the server before installing SQL Server and everything else…