• You can't disable the ability to have Windows Logins. You can only not create Logins linked to Windows accounts. You could also write a Logon Trigger that checks the login type and denies access to Windows Logins. It would contain information sort of like this:

    IF EXISTS(SELECT * FROM sys.server_principals AS SP WHERE [name] = SUSER_SNAME() AND type_desc IN ('Windows_Login', 'Windows_Group'))

    BEGIN

    RAISERROR('Windows LOGIN''s are NOT allowed ON this SERVER', 16, 1)

    END