title: Under which circumstances does the System process (PID 4) retain an open file handle?
body: <p>My application running on a Windows server makes use of a Jet/Access database. For some reasons around every two weeks that database file gets locked by the System process (PID 4, seems to be fixed)</p>
  
  <p>After some googling I found some other users having their files locked by that special process, but different files (of course).</p>
  
  <ul>
  <li>What's the general reason for the System process to keep an open file handle?</li>
  <li>Is my application the cause for this locking situation?</li>
  <li>Are all handles implicitly opened by the System process? I could imagine that after a process has crashed, the handle may still be open and the System process somehow takes owernship of that handle.</li>
  <li>Can I do something in my application to prevent it from happening?</li>
  </ul>