Short answer. Merchant Center reports “Reused value [id]” when more than one product in a feed carries the same id; each product must have a unique id, and only one of the rows is kept. Give every variant its own id (usually the variant’s SKU or database id, not the parent product’s), and keep ids stable across uploads.
| Shown in Merchant Center as | Reused value [id] |
|---|---|
| Attribute | id |
| Effect | Product disapproved — The duplicate row is not processed |
| Where to find it | Products → Needs attention, then filter by this issue |
| Free check | Reported by the free feed check |
What Merchant Center means by “Reused value [id]”
The id attribute is the product’s name inside Merchant Center: the specification requires it to be unique per product and stable over time, up to 50 characters. When two rows in one feed carry the same id, Google reports “Reused value [id]”, listed as id_reuse in the Content API’s product issues reference, and processes only one of them. The product that was on the discarded row is simply not in Merchant Center.
Because the id also carries the product’s history (approval state, performance data), changing ids to work around a duplicate resets that history. The right fix is an id that is unique and permanent, which usually means the variant’s identifier rather than the product’s.
Why it happens
- Parent id on every variant. An export writes one row per size or colour but uses the parent product’s id for each, so a product with six sizes produces six rows with one id.
- SKU reused across products, or a blank SKU on many products that the export falls back to.
- The same product in two collections exported twice by a tool that iterates collections rather than products.
- Two feeds for one country with overlapping products; the second fetch overwrites the first within the account.
How to fix it
In Shopify
Use the variant id, not the product id, as id; Shopify’s channel does this by default and so does our integration, which also uses the product id as item_group_id so the variants stay grouped. If a feed app lets you choose SKU as the id, make sure every variant has a distinct SKU first, or leave it on variant id.
In WooCommerce
Variations have their own post ids in WooCommerce, and that is what should be the feed id, with the parent’s id as item_group_id. Our free connector writes exactly that pair, so a variable product with twelve variations yields twelve distinct ids and one group. If you export by SKU, Products → Filter by “no SKU” shows the products that would collide.
In a CSV or XML feed
Sort the file by id and look for adjacent duplicates, or use a pivot table. For each duplicate, decide whether the rows are variants of one product (give each its own id and set the shared item_group_id) or the same item exported twice (delete one). Then keep the ids you chose: an id that changes on every export is a product that starts from zero each time.
How long until Merchant Center clears it
On the next fetch with unique ids, every row is processed and the issue disappears; allow 24–72 hours for the Needs attention page. Rows that were previously discarded appear as new products and go through initial review like any new item.
What FeedRobin does about it
The free check counts rows whose id is already used by another item and reports it as critical, because two items sharing an id can make Merchant Center reject more than the pair. We keep the first of each and never serve a duplicate, and the report says so. Which of two rows is the real product is a question only your catalogue can answer, so we do not merge or rename them for you. For connected stores the ids are the platform’s variant ids, which cannot collide.
Questions merchants ask
Which row does Google keep when ids repeat?
You should not rely on either. In practice the later row overwrites the earlier one within a fetch, so which variant survives depends on export order. Treat any duplicate as a product that is missing.
Should the id be the SKU or the variant id?
Whichever never changes. Google ties the product’s history and performance to its id, so an id that changes when you rename a SKU resets that. Database variant ids are the safest choice.
Can the same id appear in two different feeds?
Within one Merchant Center account and target country, the same id across two feeds is the same product, and the later feed overwrites it. Use different feeds for different countries, not for different product sets with overlapping ids.
Sources
- ID [id] — Google Merchant Center Help
- Product issues (Content API for Shopping): the issue codes and the titles Merchant Center shows — Google Merchant Center Help
- Product data specification — Google Merchant Center Help