Cannot log in using SA with SQL Authentication I can not log in to SQL Server 2008 using SQL Server authentication.

I can only log in using Windows Authentication Mode.

I chose only defaults while installing SQL Server 2008 R2.
Did you look anywhere? Right-click the server and choose Properties, then select the Security screen.


  


Then, log in using your Windows auth admin account, and set the password for the sa SQL auth account.

ALTER LOGIN sa WITH PASSWORD = 'strong password here';