When posting a voucher with a duplicate invoice number, the edit report will show a warning indicating there is already a voucher with this invoice number. Posting will still be allowed, however.
To prevent duplicate invoice numbers, do not post when receiving this warning. Go back to item entry and change the invoice number to one that hasn't been used previously for this vendor.
Steps to Duplicate
- Create a new admin voucher
- Enter an invoice number
- Go to processes and post this voucher to open items.
- Go back to item entry and create another admin voucher for the same vendor
- Enter the same invoice number
- Post again from processes
- Notice in open items two items with same vendor and invoice number, but different voucher number.