At the end of any bank period there can be deposits entered in Sage 50 that did not get deposited in the bank. The same can happen with cheques/payments that are processed through Sage 50 but not presented to your bank for payment. In either case, this will leave unresolved items on your bank reconciliation. The actual items should show in the list of transactions without a check mark. These are not unusual situations and should be expected when reconciling a bank account. These items will also remain on the reconciliation until they are actually cleared the next month.

Is it possible an entry was reversed and has put a debit or credit on the other side that you just need to check off?

TLS2007:

You stated there are data integrity errors. If your data is out of balance we will need to see the Data Integrity screen. On the left is your General Ledger and on the right side is your subsidiary ledgers. In most cases these can be corrected!