Hi, XS11E.
If the ending balance reconciles, then the opening balance is of only academic interest.
If the ending balance does NOT reconcile, then you need to identify the non-reconciling item, even if it occurred in some earlier period.
Quite often, a check or deposit that is outstanding on April 30 will clear in May. Note that a reconciliation is not really for "a month" or other PERIOD of time, but AS OF a particular POINT in time, usually the close business on the last day of a month.
Quicken's reconciliation screens sometimes confuse me. The lists of Payments and Checks and of Deposits are usually all or mostly shown as BOLD. To make it easier on myself, I click Mark All - and then Mark All a second time - to UNbold them all. And then I click each one as I compare the cleared items from my checkbook (yes, I still also keep a manual checkbook) or Quicken check register to the statement. If the "Difference" is not zero when I finish this exercise, then I have more tracking and comparing to do.
If I forgot to reconcile last month, then the screen that opens when I click Reconcile might show an "Opening Balance" that was actually from the last time that I did reconcile - maybe a few months ago. That doesn't matter, so long as all the reconciling items match the statements I've received since then. Only the ENDING balance matters.
If all else fails, go back and reconcile LAST month-end again.
I know all this is too elementary for you, XS11E - but we all have to go through these steps - again - sometimes. ;^}
RC