Thanks for you reply. An item previously reconciled on Sep 2017 was showing in the reconcile window.  I went to the register and noticed it was unchecked, so I clicked on the checkmark to make it show as reconciled. After doing that, all previous reconciliations of that account  are off by that amount, at least back to 2015, that is the oldest printed reports I have on hand. So there is obviously some kind of glitch o maybe the file got corrupted.