Adagio Payables will allow creation of $0 non-printing manual checks, but indeed will not allow creation of negative checks.

As you responded in an earlier posting, there is a $3500 credit on the vendor account. Is this an invoice or credit note with a net $3500 CR amount, or is it an unapplied payment? You also had posted that the net outstanding balance of the vendor was zero, which would logically assume that there are other transaction(s) on the vendor record that net to a $3500 DR amount.

You also posted there was an invoice from Aug 1, 2003 and a check from Aug 26, 2003. If all of this is taken together, I could assume that the invoice is a $3500 debit, and the payment is a $3500 credit? And that the payment is not applied to the invoice? The Vendor Transaction report for this vendor would list all of this for you (including the Current Amount) - make sure the end date is something like year 2099 to make sure nothing was posted in the future by mistake.

As the integrity check is clean, it would seem reasonable that if you create a manual check entry for that vendor, edit/select the check first and then the invoice (and any/all other transactions on the grid) and the total payment should net to zero, because the total outstanding for the vendor is zero. If the program is preventing this, could you indicate what sort of error or warning you are receiving?

Was the invoice adjusted to zero, leaving an unapplied check for $3500 CR on the account? That likely isn't the case if the net outstanding is zero and no DIC errors exist. It would be useful to know the list of current transactions and their respective current amounts.