title: Microsoft sql server error 18456 login failed for user
body: <p>I have installed MSSQL 2012 on Windows 2012 Server using the following settings:</p>
  
  <p><img src="https://i.stack.imgur.com/6ZzlT.png" alt="enter image description here"></p>
  
  <p><img src="https://i.stack.imgur.com/GUqfD.png" alt="enter image description here"></p>
  
  <p>But when I try to login (The username is my local user that I log-on to windows 2012 server with) I get (default instance name = MSSQLSERVER):</p>
  
  <p><img src="https://i.stack.imgur.com/96pd6.png" alt="enter image description here"></p>
  
  <p><img src="https://i.stack.imgur.com/MsdTa.png" alt="enter image description here"></p>
  
  <p>I have looked at:</p>
  
  <p><a href="https://stackoverflow.com/questions/1393654/how-can-i-change-from-sql-server-windows-mode-to-mixed-mode-sql-server-2008">How can I change from SQL Server Windows mode to mixed mode (SQL Server 2008)?</a></p>
  
  <p><a href="http://vsstack.blogspot.in/2013/11/microsoft-sql-server-error-18456-login.html" rel="nofollow noreferrer">http://vsstack.blogspot.in/2013/11/microsoft-sql-server-error-18456-login.html</a></p>
  
  <p>but that guide assumes there is already a DB available that I can enable authentication for. This is not the case. What am I missing? Do I need to re-install MSSQL to select Mixed Mode?</p>
  
  <p>EDIT: In this case it seems its only possible to change to Mixed Mode by messing around in the Registry, bummer:
  <a href="http://www.top-password.com/knowledge/sql-server-authentication-mode.html" rel="nofollow noreferrer">http://www.top-password.com/knowledge/sql-server-authentication-mode.html</a></p>
  
  <p>AND BUYING this
  <a href="http://www.top-password.com/purchase.html" rel="nofollow noreferrer">http://www.top-password.com/purchase.html</a></p>
  
  <p>to update the sa password afterwards. Maybe they should consider writing that as a warning in the installation wizard!</p>
  
  <p>It will take a couple of days to uninstall MSSQL 2012:
  <a href="https://www.youtube.com/watch?v=FvjjU8nPrRc" rel="nofollow noreferrer">https://www.youtube.com/watch?v=FvjjU8nPrRc</a></p>
  
  <p>So maybe the best solution is to re-install windows?</p>