# Duplicates

How Cortena groups related documents by supplier and invoice number (optional total / PO / delivery / quote), picks a master, and excludes duplicates from export.

When the same invoice arrives twice (email resend, invoice plus receipt, or overlapping uploads), Cortena **groups duplicates** and picks one **master** row for export and workflow. Related copies appear linked underneath.

Configure matching strictness under **Settings → Invoice Import**. See [Configure duplicate detection](https://help.cortena.ai/guides/invoices/configure-duplicate-detection).

**Who this is for:** AP teams who want to avoid exporting the same supplier invoice twice or hunting related PDFs manually.

## 1. How duplicates are detected

Cortena groups documents for the **same supplier**:

1. Prefer the **linked master supplier** when Cortena has matched the creditor.
2. Otherwise use the **extracted supplier name**.

**Primary match:** both documents have the same non-empty **invoice number**. By default they must also share the same **total amount** (you can turn that off under **Settings → Invoice Import**).

**Secondary match (optional):** if an invoice number is missing, Cortena can also group documents that share the same **purchase order**, **delivery**, or **quote** number, when those options are enabled in Invoice Import. Matching is always same-type only (PO to PO, not PO to delivery). If both documents have invoice numbers that differ, they are **not** linked via those other numbers.

Invoice **date** is not used for matching.

The **master** is usually the most invoice-like document (actual invoice beats receipt or delivery note). Among equals, the **oldest import** wins master status.

Full option list and recommended setups: [Configure duplicate detection](https://help.cortena.ai/guides/invoices/configure-duplicate-detection).

## 2. List display

In **Payables**:

- **Master** rows appear at normal indent with a checkbox for bulk actions.
- **Duplicate** rows sit indented, greyed, **without checkbox**. They cannot be bulk-exported.
- **Select all** skips duplicates automatically.

Use filter **Duplicates → Master only** to hide related copies. Pulse uses the same preset for queue counts.

## 3. Receipts and payment status

If a duplicate is a **receipt** and the master is an unpaid **invoice**, Cortena may mark the master **Paid** and link the receipt, saving a manual payment status update.

Review the master's **Payment status** tooltip to see why it was marked paid.

## 4. Managing duplicate groups

| Action | Effect |
| --- | --- |
| **Delete duplicate** | Removes only the copy · master stays |
| **Promote to master** | Swaps roles when the wrong file became master |
| **Remove duplicate link** | Breaks group when files are not actually duplicates |

Open the master detail → **Duplicates** section for group actions.

## Quick reference

| Topic | Behaviour |
| --- | --- |
| Supplier key | Master supplier if linked, else extracted name |
| Primary match | Same invoice number (+ total by default) |
| Secondary match | Same PO / delivery / quote when enabled and invoice # missing |
| Settings | [Configure duplicate detection](https://help.cortena.ai/guides/invoices/configure-duplicate-detection) |
| Export | **Master only** |
| List filter | Duplicates: **Master only** |
| Receipt duplicate | May auto-mark master **Paid** |
| Wrong master | **Promote to master** on detail |