Fix "Invalid or duplicated SKU" in a WooCommerce import
Exact error message
- A product with this SKU already exists.
- Invalid or duplicated SKU.
WooCommerce skips a row when its SKU is already taken, either by another row in the same file or by a product already in your store. If you meant to update those products, tick "Update existing products" in the importer. If not, every SKU must be unique: the tool lists each duplicate in your file so you can fix them before importing.
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Why it happens
Both messages come from WooCommerce's own code. "A product with this SKU already exists." appears when you import without "Update existing products" and the SKU is already used in your store. "Invalid or duplicated SKU." comes from saving the product, when another product or variation already has that SKU.
SKUs must be unique across all products and variations, not just within one product.
- The same SKU on two rows of the file, often a parent and its variation, or two variations.
- A product with that SKU already in the store, imported without "Update existing products".
- A draft or private product in the store that still holds the SKU.
- A spreadsheet that turned SKUs such as 00123 into 123, or long numbers into 1.23E+12, so two different SKUs became identical.
How to fix it manually
Excel
- Select the SKU column, then Home → Conditional Formatting → Highlight Cells Rules → Duplicate Values.
- Make each highlighted SKU unique, or delete the duplicate row.
- Format the SKU column as Text before pasting, so leading zeros survive.
WooCommerce
- To update products that already exist, tick "Update existing products" on the importer's first screen. Rows are matched by ID or SKU.
- Search the products list for the SKU, including drafts, to find which product holds it.
Before and after
Type,SKU,Name,Parent,Attribute 1 value(s)
variable,BEANIE,Wool beanie,,
variation,BEANIE-RED,,BEANIE,Red
variation,BEANIE-RED,,BEANIE,BlueType,SKU,Name,Parent,Attribute 1 value(s)
variable,BEANIE,Wool beanie,,
variation,BEANIE-RED,,BEANIE,Red
variation,BEANIE-BLUE,,BEANIE,BlueA copied row kept the SKU of the red variation. WooCommerce would skip the blue one. You decide which SKU is right; the tool shows you where.
Fix it automatically
- Finds every SKU used more than once in the file and shows all the rows that share it.
- Flags variations without a SKU or GTIN and can generate SKUs for them from the parent and attributes.
- Leaves duplicate SKUs for you to resolve, because only you know which product the SKU belongs to.
- Checks that every Parent points to a SKU in the file.
Checking and the preview are free. Downloads are free up to 50 rows; a larger file costs 1 credit.
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