When you import products into the Products Catalog, 3Dsellers uses a match and merge process to avoid creating duplicate catalog entries. Understanding how this works helps you import cleanly and fix issues when they come up
How matching works
When importing, 3Dsellers compares each incoming product against existing catalog products using a field you choose. By default that field is SKU. If a match is found, the product is treated as one you already have. If no match is found, a new product is created.
You can change this in the Advanced matching rules section at the bottom of the import popup. You can match by: SKU, Title, UPC, EAN, ASIN, MPN, or ISBN, and you can add a second field for more precise matching (for example, SKU + Title). The popup shows your rule in plain English underneath, for example: Products will be matched where SKU equals SKU.
What happens when a match is found
You decide this in the import popup, under If product already exists in catalog. There are three options:
Import new products only - anything already in the catalog is skipped. Only listings with no match are imported.
Merge - missing fields are filled in. Data already in the catalog is never changed.
Override - the imported data replaces what is in the catalog.
Depending on which one you pick, this can affect title, description, pricing, images, inventory, categories, tags, and custom attributes.
📌 Check which option is pre-selected before you click Import. The default is not the same everywhere.
What are duplicate SKUs and why do they cause problems?
A duplicate SKU occurs when two or more listings on the same selling channel share the same SKU. Since 3Dsellers uses SKUs to match and sync listings with catalog products, each SKU must be unique per channel. If duplicates exist, 3Dsellers cannot reliably link the listing to the correct catalog product, so those products cannot be imported.
How to find and fix duplicate SKUs
After an import, any products that couldn't be imported due to duplicate SKUs are flagged automatically.
To fix them:
Go to Products Catalog → Import → Duplicate Products.
You'll see a list of channels with duplicate SKU counts.
Click View and Fix next to the affected channel.
You'll be taken to the Duplicate SKU segment inside Listings Manager, where all affected listings are grouped.
From there you have several options:
Edit the SKU manually using the pencil icon to give each listing a unique SKU.
Use Auto Fix Duplicate SKUs to let 3Dsellers assign unique SKUs automatically.
Use SKU Generator to apply a custom SKU pattern across selected listings.
If the listings are genuinely the same product and the duplication is intentional, click Mark as not Duplicate SKU.
Once SKUs are unique, re-import the products into the catalog.
Tips
If you sell the same physical product across multiple channels (e.g., eBay US and eBay UK), each channel connection is treated separately, so duplicate SKU rules apply per channel, not globally.
Using Auto Fix is the fastest option for large batches, but review the results if SKU naming matters for your workflow.
If you only want to add items that are not in the catalog yet, choose Import new products only. If you want to fill gaps in existing products without overwriting anything, choose Merge.
Troubleshooting
1) The number of catalog products is lower than the number of listings I imported
This is expected behavior when multiple listings share the same SKU or match on the same field. When 3Dsellers finds a match, it merges the incoming listing into the existing catalog product rather than creating a new one. So if 5 listings all have the same SKU, they will all merge into a single catalog product. The catalog count reflects unique products, not total listings.
If this is not what you intended, check whether your listings have truly unique SKUs before importing. You can use the Duplicate SKU segment in Listings Manager to review.
2) A product was imported but it's not linked to the listing
This can happen if the match field used during import (e.g., SKU) does not exactly match the SKU on the live listing. The catalog product gets created but the listing-to-product link is not established. Check that the SKU on the listing in Listings Manager matches exactly what was imported, including spacing, capitalization, and special characters.
3) The import ran but nothing changed in the catalog
This usually comes down to which option was selected under If product already exists in catalog:
Merge only fills in empty fields. If the matching catalog product already had values, nothing visibly changes.
Import new products only skips every product that is already in the catalog, so an import over an existing catalog can look like it did nothing.
Re-run the import with Override selected if you need to refresh existing products with the latest channel data.
4) Inventory didn't update after import
Inventory is only imported if the source listing has available quantity data. Check the Set inventory location to option under "Apply to imported products" in the import popup. If you did not select a location, 3Dsellers assigns the stock to a warehouse based on the listing's own location data from the channel, so the quantity may have landed in a different warehouse than you expected. Also note that if a product already exists in the catalog and you used Merge or Import new products only, the existing inventory value is kept.
5) Some products were imported but others were skipped
Products are skipped when they have duplicate SKUs that couldn't be resolved, when Import only products with available quantity is enabled and some listings have zero stock, or when Import new products only was selected and those products already existed in the catalog. Check the Duplicate Products page and your import settings to identify which products were excluded and why.
6) A product appears in the catalog but shows the wrong title, price, or images
If Override was selected during a previous import, the catalog product may have been overwritten by data from a different listing than expected, particularly if multiple listings matched on the same field. Review the match field being used and ensure it uniquely identifies the intended product. If needed, edit the catalog product manually or re-import with more specific match criteria.
7) After fixing duplicate SKUs, the product count still doesn't match
Fixing duplicate SKUs in Listings Manager only resolves the SKU conflicts, you still need to re-run the import after fixing them. Go back to Products Catalog → Import and import again. The Duplicate Products page should clear once all SKUs are unique and the import completes successfully.
Merging products manually after import
The matching described above happens automatically during import. If products have already landed in your catalog as separate entries and should be one, you can combine them yourself with the Merge Products bulk action.
Go to Products Catalog → All Products, select 2 or 3 products, then click Bulk Actions → Merge Products. A short wizard walks you through choosing the primary product that stays, resolving any channel conflicts, picking which product each field's data comes from, and reviewing everything before you confirm.
This is useful when:
The same item was imported twice under different SKUs
The same product is listed on different channels as separate catalog products
Two similar products should be tracked and synced as one
Two things to keep in mind: merges are limited to 2 or 3 products at a time, and a merge cannot be undone from the catalog. Listings you do not keep during a channel conflict are ended on that channel, so review the final step carefully before confirming.