title: Web flow Exception: No flow execution snapshot could be found with id '1'
body: <p>I am getting below exception whenever I switch one state to another more then 15 times in web-flow.  </p>
  
  <pre><code>No flow execution snapshot could be found with id '1'; perhaps the snapshot has been removed? . Stacktrace follows:
  org.springframework.webflow.execution.repository.FlowExecutionRestorationFailureException: A problem occurred restoring the flow execution with key 'e7s1'
  at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
  at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
  at java.lang.Thread.run(Thread.java:662)
  Caused by: org.springframework.webflow.execution.repository.snapshot.SnapshotNotFoundException: No flow execution snapshot could be found with id '1'; perhaps the snapshot has been removed? 
  ... 3 more
  </code></pre>
  
  <p>I am using grails webflow plug-in.</p>
  
  <p>Are anyone have any idea why this is occurring and how to resolve this? </p>