Change Server Authentication Mode
This topic describes how to change the server authentication mode in SQL Server 2017 by using SQL Server Management Studio or Transact-SQL. During installation, SQL Server Database Engine is set to either Windows Authentication mode or SQL Server and Windows Authentication mode. After installation, you can change the authentication mode at any time.
If Windows Authentication mode is selected during installation, the sa login is disabled and a password is assigned by setup. If you later change authentication mode to SQL Server and Windows Authentication mode, the sa login remains disabled. To use the sa login, use the ALTER LOGIN statement to enable the sa login and assign a new password. The sa login can only connect to the server by using SQL Server Authentication.
In This Topic
Before you begin:
To change server authentication mode, using:
Before You Begin
The sa account is a well-known SQL Server account and it is often targeted by malicious users. Do not enable the sa account unless your application requires it. It is very important that you use a strong password for the sa login.
Using SQL Server Management Studio
To change security authentication mode
In SQL Server Management Studio Object Explorer, right-click the server, and then click Properties.
On the Security page, under Server authentication, select the new server authentication mode, and then click OK.
In the SQL Server Management Studio dialog box, click OK to acknowledge the requirement to restart SQL Server.
In Object Explorer, right-click your server, and then click Restart. If SQL Server Agent is running, it must also be restarted.
To enable the sa login
In Object Explorer, expand Security, expand Logins, right-click sa, and then click Properties.
On the General page, you might have to create and confirm a password for the login.
On the Status page, in the Login section, click Enabled, and then click OK.
To enable the sa login
In Object Explorer, connect to an instance of Database Engine.
On the Standard bar, click New Query.
Copy and paste one of the following examples into the query window and click Execute.
The following example enables the sa login and sets a new password.
ALTER LOGIN sa ENABLE ; GO ALTER LOGIN sa WITH PASSWORD = '<enterStrongPasswordHere>' ; GO
The following example changes Server Authentication from mixed mode (Windows + SQL) to Windows only.
USE [master] GO EXEC xp_instance_regwrite N'HKEY_LOCAL_MACHINE', N'Software\Microsoft\MSSQLServer\MSSQLServer', N'LoginMode', REG_DWORD, 1 GO
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