You cannot finish history until all of the account balances related to the sub-ledgers agree with the balances in the sub-ledgers. For the Accounts Receivable Ledger all of the outstanding invoice balances must equal the same amounts that are shown in Account 1016 and less any deposits received from customers. At the time of this error you have a 1016 balance of $151,318.77 but only $635.00 in the ledger. You will have to add the rest of the outstanding invoices to total $151,318.77 or change the balance in the account to a more accurate amount or a combination of both. My guess is that you did not enter the individual outstanding invoices when you first setup Sage 50 for this company.