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# Unable to import a duplicate reference/SKU

When importing an order, you may see:

> Duplicate reference in catalog (XXX-YYY) — 2 products or combinations match in PrestaShop

*(Exact module string. The SKU and count vary.)*

The reference / SKU exists at least twice in PrestaShop (products or combinations). The module cannot choose which one to use.

Duplicate example:

![PrestaShop CDiscount duplicate reference example](https://storage.crisp.chat/users/helpdesk/website/-/3/f/a/8/3fa8ee645cd13200/prestashop-cdiscount-exemple-d_1onv4ro.jpg)

Every product and every combination must have a **unique** reference:

[Validate your catalog structure](https://doc.common-services.com/en/article/validate-your-catalog-structure-cdiscount-1trq16m/)

**Action:** fix the duplicate reference(s), then retry the import.