To piggy back onto what Ben621 has already expressed, the issue here is that QB says it will auto correct the payment, but it is not.  Even if a payment is being applied in full to an invoice that has a specific class assigned to it, the system is not applying that same class to the payment.  I can easily find these errors and pull up the transaction journals to see that the class field is blank for both the checking account and the A/R account.  If it was possible to edit the transaction journal entry, I could manually fix this until the Engineers at QB install a class entry field on the payments function.  Since it is a system generated journal entry, QB will not allow me to edit the class, at least as far as I know.  Any workaround you can provide for manually fixing unclassified balances would be useful.