Duplicate invoice checks: review the evidence before the payment run
In this hypothetical case, a supplier emails invoice INV-2048 for 1,850 to the shared accounts inbox, and a colleague uploads the same PDF through the purchasing tool. Two bills now wait for approval. Deleting one at random might remove the record that already carries its approval trail, and approving both risks paying one obligation twice. A lookalike pair is an exception for someone to investigate and clear, with a recorded reason, before the payment run.
Decide what makes two invoices the same
We suggest a review key built from the paying legal entity, supplier identity, invoice reference, currency and amount, with invoice date and the period covered used to interpret a match. Keep the supplier's reference exactly as issued. A separate comparison field can ignore spacing or letter case for searching while the original stays untouched.
Looser matching finds more candidates and more false alarms. Stripping punctuation or leading zeros can make different references look identical, so treat those hits as candidates for review. Never change a genuine supplier reference to get an invoice past a warning.
Investigate each candidate pair
These pairs are hypothetical, in generic currency units.
Search beyond approved bills: drafts and pending items, credit notes, earlier payments and any other name the supplier trades under. A shared processing status, or a single intake owner, shows colleagues that an invoice is already being handled and lowers the chance of a second entry.
| Candidate pair | What the reviewer checks | Possible outcome |
|---|---|---|
| Same supplier, entity and reference INV-2048 for 1,850, one from the inbox and one uploaded | Both attachments, the goods or service, and whether either bill is already approved or paid | One obligation entered twice. Keep the original, correct the duplicate with an audit trail and hold it from payment. |
| Same supplier and amount of 500, references SEP-26 and OCT-26 | The service months covered and the contract | Two monthly charges. Keep both if the contract supports them. |
| Same reference and amount, billed to two legal entities | The addressee on each invoice and which entity received the goods or service | One may belong to the other entity, or the supplier may need to clarify. Different entity codes alone do not clear the alert. |
Test the control your software runs
Microsoft's documentation for Dynamics 365 Finance describes a check that stops an invoice being submitted to workflow when its number matches another posted invoice. It applies when the relevant feature is enabled and the 'Check the invoice number used' setting is 'Reject duplicate'.
That check compares against posted invoices and depends on configuration. It says nothing about how your setup handles drafts, imports, near-matches or other legal entities, and a number check alone will not catch every route to a double payment. Test your own workflow with a dummy pair, in a test environment where you have one, and keep manual review for the gaps you find.
Sources and context, checked :
Clear the flag before payment
Before the run is released, record who cleared each flag and why. If a duplicate has already been paid, deleting the second bill does not recover the cash. The supplier needs to refund or credit it, and the accounting needs correcting. Where a closed period or a tax return is affected, the responsible accountant should handle the correction.
Before your next payment run, export the bills awaiting payment, sort them by supplier and amount, and investigate every pair that shares a supplier with the same amount or reference. Attach the reason for each decision to the bill.