After publishing a new workflow, you may encounter a problem where some existing workflows no longer process documents. This can occur if the SSAdministrator (or whichever service account you are using) does not have permission to the new workflow's Initiator search.
This will cause one of two possible errors that can be found in the GlobalAction log. By default, the GlobalAction log can be found in "C:\GetSmart\Workflow.log".
ENGINE: CRITICAL ENGINE ERROR, UNHANDLED EXCEPTION REFLECTED TO TASK RUNNER.
ENGINE: CRITICAL: Index was out of range. Must be non-negative and less than the size of the collection.
ENGINE: Error occurred polling workflow initiator for <WORKFLOW NAME>: User does not have permission to the selected Search or it does not exist.
Under most circumstances, you should not have the SSAdministrator explicitly secured to your database. Instead, make sure that the SSAdmin group has full permissions across your database. Because the SSAdministrator is a member of this group, those permissions will be inherited.