title: Is File.Exists an expensive operation?
body: <p>Re: <a href="http://msdn.microsoft.com/en-us/library/system.io.file.exists.aspx" rel="noreferrer">http://msdn.microsoft.com/en-us/library/system.io.file.exists.aspx</a></p>
  
  <p>Does anyone know if this is a particularly slow or locking operation which could impact server performance in a large environment?</p>