What might be causing an 'Activity Instance Does not exist' exception in my workflow code?

Question

I am debugging some workflow code. I have found the following code is throwing the exception 'activity Instance(tcm:10-2988-131104) does not exist.'

private ActivityInstance FinishActity(ActivityInstance instance, string message,
                                      Trustee nextAssignee, Session userSession)
{
  try
  {
    ActivityFinish finishActivity = new ActivityFinish(message, nextAssignee, userSession);
    return instance.Finish(finishActivity);
  }
  catch (PermissionDeniedException)
  {
    return null;
  }
  catch (InvalidActionException)
  {
    return null;
  }
}

It seems like the activity instance no longer exists when execution reaches the statement return instance.Finish(finishActivity)

Is there an activity instance timeout that might be the cause of this?

If so, where would I configure that timeout?

Sometimes when activity is finished it is not appearing in assignment list. But we can see that in global work list. When we initiate the workflow for some other item then along with new item the previous item also appear in the assignment list. I am feeling in the above scenario the second time when workflow start it triggers the previous workflow as well.

Answer 1

Activity instances don't expire. They get terminated or finished either manually or automatically through code.

It is likely that your ActivityInstance has ended, and it has become an ActivityHistory at the moment you are trying to finish it.

For the record: I notice you are using TOM.NET in your code. That is not officially supported (TOM.NET is only valid to be used inside templates and event system). Please consider using Core Service as supported API from workflow.