New duplicate transactions (Q Mac)

ksevareid

Been using Quicken without much problem for over four years, reconciling bank accounts monthly. Trying to reconcile a credit card account today: beginning balance is correct, enter closing date and balance; Quicken says there is a difference amounting to ~ half of the statement balance.
Go to reconciliation history window, Q says previous two statements have multiple discrepancies. ( I know for a fact I reconciled last two statements.) Go and look in the register and there appear to be duplicate transactions for most if not every entry; new entries show as downloaded from bank, cleared but not reconciled. New entries appear to coincide roughly with the previous two statements.
How do I begin to unravel this mess?
thanks in advance for any guidance,

Karl Sevareid