title: SQL Server Express unable to attach or delete mdf file
body: <p>My database file <code>Whist.mdf</code> was attached to a SQL Server Express through Management Studio, but it stopped working in that sense that NHibernate in my asp.net solution fired some connection exceptions. I just detached it from Management Studio because I couldn't open the database in there either.</p>
  
  <p>But when I try to reattach it I get this error:   </p>
  
  <blockquote>
    <p>Attach database failed for Server 'MyPCName\SQLECPRESS'. (Microsoft.SqlServer.Smo) Unable to open the physical file "C:\Program
    Files\Microsoft SQL Server\MSSQL10.SQLEXPRESS\MSSQL\DATA\Whist.mdf".
    Operating system error 32:  "32(process cannot access the file because
    it is being used by another process)". (Microsoft SQL Server, Error: 
    5120)</p>
  </blockquote>
  
  <p>I have googled it but can't find a solution that works for me. E.g.:</p>
  
  <ul>
  <li><a href="http://www.byteblocks.com/post/2010/01/06/Unable-to-open-the-physical-file-Microsoft-SQL-Server.aspx" rel="nofollow noreferrer">http://www.byteblocks.com/post/2010/01/06/Unable-to-open-the-physical-file-Microsoft-SQL-Server.aspx</a></li>
  <li><a href="https://stackoverflow.com/questions/8528768/cannot-open-user-default-database-login-failed-after-installing-sql-server-m">&quot;Cannot open user default database. Login failed.&quot; after installing SQL Server Management Studio Express</a></li>
  </ul>
  
  <p>There is something about User Instance but I cant figure out if it have anything to do with that:</p>
  
  <ul>
  <li><a href="http://blogs.msdn.com/b/sqlexpress/archive/2006/11/22/connecting-to-sql-express-user-instances-in-management-studio.aspx" rel="nofollow noreferrer">http://blogs.msdn.com/b/sqlexpress/archive/2006/11/22/connecting-to-sql-express-user-instances-in-management-studio.aspx</a></li>
  </ul>
  
  <p>I have tried to delete the mdf file in windows but I can't do that either:</p>
  
  <blockquote>
    <p>The action can't be completed because the file is open in system</p>
  </blockquote>
  
  <p>I have tried stopping the SQL Server process, closing explore and delete from cmd and rebooting...</p>
  
  <p>Hope someone can help - I guess it is just a simple thing..</p>