I was in the process of answering you against the grain here, as everyone was saying it is index related and that is not always true in my experience, just 3 weeks ago I was chasing the same problem and the error name got me chasing ghosts, as I also thought it was index related, but it turns out it was not, now, I asked my co-worker and he also forgot what did I tell him the problem was, that is why I did not reply, I am looking into the tickets to try to find out what it was and how did I solve it, unfortunately, I cannot find it, I think it might have been that the file grew past 2Gb, so I am trying to test that now, but if that was the case, it will not help you at all